Cardiology AI Flashcards
1
Q
What are sinuses of Valsalva?
A
Dilations of the aortic root that lie immediately beyond the aortic valve.
2
Q
What does the left subclavian artery supply?
A
The left thoracic limb and some vertebral arteries.
3
Q
What do bronchial veins drain?
A
Systemic vessels that perfuse lung tissue and empty into the pulmonary veins.
4
Q
What is the function of the interventricular septum?
A
To contribute a critical proportion of right ventricular systolic function.
5
Q
What is the left ventricular free wall’s contribution to the cardiac mass?
A
It makes up the left and caudal aspects of the cardiac mass.
6
Q
What do Thebesian veins empty into?
A
The cavities of both left and right ventricles.
7
Q
What is the role of the right side of the heart?
A
To facilitate low pressure flow from systemic veins into the low-resistance pulmonary circulation.
8
Q
What is the cranial vena cava responsible for draining?
A
Venous drainage from the head, neck, and thorax.
9
Q
What does the caudal vena cava drain?
A
Venous drainage from the abdomen and caudal body.
10
Q
What is the function of the azygous vein?
A
It drains the dorsal walls of the abdomen and thorax and forms a physiologic anastomosis between the caudal and cranial vena cava, bypassing the cranial abdomen.
11
Q
What does the right atrium empty into?
A
The tricuspid valve orifice.
12
Q
What is the right ventricle?
A
A low-pressure conduit between the systemic veins and the pulmonary artery.
13
Q
What is the function of the tricuspid valve?
A
To act as a three-leaflet atrioventricular valve.
14
Q
What is the location of the right ventricular free wall?
A
It makes up the cranial and right-lateral aspects of the cardiac mass.
15
Q
What is the pulmonic valve?
A
A three-leaflet semilunar valve that is anatomically separate from the aortic, mitral and tricuspid valves.
16
Q
What is the function of papillary muscles?
A
To project from the myocardium and tense the valve leaflets slightly before peak systole.
17
Q
What are chordae tendinae?
A
Structures that attach the tricuspid leaflets to the papillary muscles.
18
Q
What is the main pulmonary artery responsible for?
A
Curving cranially over the aortic root and ascending aorta, then branching into left and right pulmonary arteries.
19
Q
Where is the coronary sinus located?
A
On the floor of the right atrium, just inside the entrance of the caudal vena cava.
20
Q
What is the intervenous tubercle?
A
A ridge of muscular tissue on the posterior right atrial wall that serves to stream blood flow from the cranial vena cava towards the tricuspid orifice.
21
Q
What is the fossa ovalis?
A
A region of thin, fibrous inter-atrial septum representing the site of the embryologic foramen ovale.
22
Q
How does reduced cardiac output lead to activation of neurohormonal mechanisms in heart disease?
A
Reduced cardiac output triggers activation of neurohormonal mechanisms as a compensatory mechanism.
23
Q
What are the irreversible changes in anatomy and physiology seen in patients with heart disease?
A
Patients with heart disease exhibit cardiac and vascular fibrosis, enlarged cardiac chambers, and a higher baroreceptor set-point.
24
Q
What are the causes of reduced cardiac output in specific cardiac disorders?
A
Mitral valve disease, dilated cardiomyopathy, hypertrophic cardiomyopathy, patent ductus arteriosus, aortic/pulmonic stenosis, and tachycardiac-induced cardiomyopathy.
25
How does mitral valve disease lead to reduced cardiac output?
A leak in the mitral valve causes a percentage of stroke volume to be returned to the left atrium instead of being pushed forward into the arterial system.
26
What is the mechanism of reduced cardiac output in dilated cardiomyopathy?
Muscular weakness of the left ventricle leads to reduced stroke volume and drop in cardiac output.
27
How does hypertrophic cardiomyopathy result in reduced cardiac output?
Myocardial fibrosis and abnormal force transduction lead to muscular thickening, diastolic dysfunction, and reduced stroke volume.
28
What effect does patent ductus arteriosus have on cardiac output?
Diastolic run-off of blood through the PDA reduces mean arterial pressure, unloads baroreceptors, and decreases cardiac output.
29
What is meant by 'high output heart failure'?
It refers to the reduced cardiac output caused by a large ventricular septal defect (VSD) or arteriovenous shunt.
30
How does aortic or pulmonic stenosis contribute to RAAS activation?
Severe reduction in outflow from either side of the heart activates RAAS by unloading baroreceptors.
31
How do chronic tachyarrhythmias lead to cardiomyopathy and CHF?
Tachyarrhythmias reduce cardiac output by impairing ventricular filling and causing myocardial dysfunction, triggering the baroreflex and RAAS activation.
32
What are the consequences of chronic RAAS activation on the heart?
Myocardial fibrosis, reduced diastolic function, increased risk of arrhythmias, reduced myocardial perfusion, and potential for infarction.
33
What is pressure overload and how does it contribute to cardiac remodeling?
Pressure overload occurs when the heart faces increased afterload, leading to concentric hypertrophy and thickening of the myocardium.
34
What is volume overload and how does it contribute to cardiac remodeling?
Volume overload occurs when the heart receives excessive blood volume, causing eccentric hypertrophy and dilation of cardiac chambers.
35
What is the role of myocardial fibrosis in cardiac remodeling?
Myocardial fibrosis contributes to reduced diastolic function, arrhythmias, and can lead to ischemia and potential infarction.
36
What adaptations does the heart undergo in response to the primary deficit affecting it?
The heart undergoes additional remodeling to compensate for the primary deficit and maintain cardiac function.
37
What are T-tubules in cardiomyocytes?
Long invaginations of the cell surface membrane.
38
What is the function of T-tubules?
To facilitate rapid depolarisation of the cell and reduce the distance calcium ions have to travel.
39
What is the sarcoplasmic reticulum?
A highly folded series of membranous sacs.
40
What is the function of the sarcoplasmic reticulum?
To store calcium ions and release them during systole.
41
How many types of calcium channel/pump exist in the cardiomyocyte?
Four.
42
What is the function of the L-type calcium channel?
To allow an influx of calcium into the cytosol.
43
What is the calcium-induced calcium release channel?
A large protein that opens up when activated and allows calcium ions to leave the sarcoplasmic reticulum.
44
What is the SERCA2a pump?
An ATP dependent pump that pumps calcium ions from the cytosol into the sarcoplasmic reticulum.
45
What is the sodium-calcium exchanger?
A passive, two-way channel that exchanges sodium ions for calcium.
46
What happens when the action potential arrives in a cardiomyocyte?
L-type calcium channels open and allow an influx of calcium ions into the cytosol.
47
What causes contraction of the cardiomyocyte?
Binding of calcium ions to the sarcomere.
48
How is the intracellular calcium concentration normalized at end-systole?
Through re-uptake into the sarcoplasmic reticulum and facilitated diffusion out of the cell surface membrane.
49
What are the three factors that lead to contraction of the sarcomere?
Protein structure of the sarcomere, influx of calcium to the cytosol, and ATP release.
50
What are actin and myosin?
The two crucial proteins of the sarcomere that interact via binding sites.
51
What is the state of the sarcomere during diastole?
Relaxed, with myosin heads prevented from activity by troponin proteins.
52
What happens when there is an increased intracellular calcium ion concentration?
A change in the sarcomere leading to contraction.
53
Who is the Module Developer of Small Animal Medicine Distance Learning Module 12?
Dr Kieran Borgeat
54
Who are the Module Tutors of Small Animal Medicine Distance Learning Module 12?
Dr Brad Gavaghan and Dr Fiona Meyers
55
What are the learning objectives of Week 1 of Small Animal Medicine Distance Learning Module 12?
1. Describe and recognise the anatomy of the left side of the heart and its relationship to the great vessels
2. Describe and recognise the anatomy of the right side of the heart and its relationship to the great vessels
3. Integrate this information of the heart as a 2-dimensional structure into 3-d anatomy
4. Understand the basic anatomy of the conduction system of the heart
5. Identify the difference between the atrial and ventricular action potential, and describe how pacemaker cells are different
6. Describe calcium cycling within the cardiomyocyte and the role of various transporters and receptors in excitation-contraction coupling
7. Describe the ultrastructure of the sarcomere and how contraction of the myocyte is initiated
8. Relate blood pressure, heart rate, stroke volume, vascular resistance and cardiac output through two basic equations and predict how these variables will change in states of exercise and haemorrhage
9. Describe the renin-angiotensin-aldosterone system and how it contributes to clinical signs of congestive heart failure
10. Contextualise the primary problem in three commonly acquired heart diseases and how they lead to RAAS activation
11. Appreciate the basic principles of cardiac remodelling and integrate this with clinical conditions in order to predict what sort of cardiac remodelling will occur
56
What is the structure and function of the ascending aorta?
It is a large, elastic vessel centrally located within the heart that recoils after filling to generate arterial flow.
57
What is the function of the brachiocephalic trunk?
It is the first aortic branch that gives rise to the left and right carotid arteries and the right subclavian artery.
58
What is the role of the pulmonary veins?
They drain oxygenated blood from the lungs back to the left heart.
59
Describe the left atrium. What is its function?
The left atrium is a low-pressure receiving chamber from the pulmonary circulation.
60
What is the purpose of the left auricle?
It is a blind-ending pouch on the cranio-lateral aspect of the left atrium, representing the embryologic left atrium.
61
What is the primary function of the left ventricle?
It is the heart's primary pump responsible for driving blood into the arterial system.
62
Why is the aortic valve of critical importance?
It maintains systemic arterial pressure and tissue perfusion.
63
What is the mitral valve? What is its role?
The mitral valve is a bicuspid atrioventricular valve that prevents significant back-flow of blood into the left atrium during ventricular systole.
64
What is the purpose of the conduction system in the heart?
To generate coordinated contraction that maximizes stroke volume.
65
Where is the sino-atrial node located?
In the high right atrium wall.
66
What structures join the sino-atrial node and pass electrical impulses into the left atrium?
Inter-nodal pathways.
67
Where is the atrioventricular (AV) node located?
On the floor of the right atrium.
68
What is the function of the fibrous AV annulus?
To electrically isolate the atria from the ventricles, except at the AV node.
69
Which structure descends the basilar interventricular septum from the AV node?
Bundle of His.
70
What divides off the bundle of His and carries impulses to each ventricle separately?
Left and right bundle branches.
71
Where are the tiny, terminal branches of the conduction pathways located?
Purkinje fibres.
72
What happens to the electrical impulses after leaving Purkinje fibres?
They travel on a slower pathway via gap junctions between cell membranes.
73
Why is the conduction in the AV node naturally slow?
To allow the atria to contract and prime the ventricles before they contract.
74
What is the purpose of the atrial-ventricular relationship and timing?
To maximize cardiac output by synchronizing atrial and ventricular contractions.
75
Which ventricle finishes ejection slightly earlier, following depolarization?
The left ventricle.
76
What do deep S waves in lead II suggest?
Right ventricular enlargement.
77
What is the resting membrane potential of a cardiomyocyte?
Around -80 mV.
78
What happens if the cardiomyocyte is depolarized to a threshold potential?
A coordinated sequence of ion channel opening and closing is initiated.
79
How does the atrial action potential differ from the ventricular action potential?
The atrial action potential has little sodium channel involvement and does not have a calcium-induced plateau.
80
Where are pacemaker cells located?
Throughout the conduction system, but primarily in the sinoatrial node.
81
What is the function of lower order pacemakers in the heart?
To act as backup pacemakers in cases of sinoatrial node dysfunction or atrioventricular block.
82
What is the process that links electrical impulses to contraction in the heart?
Excitation-contraction coupling.
83
Which ion is crucial for maintaining excitation-contraction coupling in cardiomyocytes?
Calcium.
84
What are the two structural features of cardiomyocytes that assist in rapid calcium ion cycling?
Specialized channels and receptors, and calcium ion flow within the cytosol.
85
What does the troponin complex shape look like?
The troponin complex has a specific shape.
86
What happens when calcium ions bind to troponin C?
Calcium ions bind to troponin C and remove the inhibitory troponin subunit.
87
What happens when myosin heads bond to actin?
Myosin heads induce a conformational change, shortening the sarcomere.
88
What is the process called when myosin heads bond to actin?
The process is called cross-bridge formation.
89
What is the role of calcium ions and ATP molecules in sarcomere shortening?
They contribute to the ratchet-like action that pulls the molecules over one another.
90
What happens after calcium dissociates from troponin C?
The troponin complex reverts to its inactive state and the binding site is covered.
91
What are the basic functional equations in cardiovascular physiology?
The equations are blood pressure = (cardiac output) x (systemic vascular resistance) and cardiac output = (stroke volume) x (heart rate).
92
What are the cornerstones of survival for reduced cardiac output?
The activation of baroreceptors and the renin-angiotensin-aldosterone system (RAAS).
93
Why do compensatory mechanisms in heart failure become maladaptive?
They increase myocardial workload in a hypofunctional heart and accelerate the disease process.
94
What is the role of the baroreceptor reflex?
It prevents loss of consciousness when standing up or experiencing changes in vascular resistances and cardiac output.
95
What triggers the renin-angiotensin-aldosterone system?
Detection of reduced renal blood flow by the nephron triggers the system.
96
What are the negative results for cardiac patients from the renin-angiotensin-aldosterone system?
Increased blood volume, increased afterload, reduced vagal tone, sympathetic activation, and cardiac remodelling and fibrosis.
97
Do the compensatory mechanisms in cardiac patients remain activated chronically?
Yes, unless treated surgically or with a heart transplant.
98
Are the compensatory mechanisms meant for chronic activation in the heart?
No, they are not meant for chronic activation.
99
What does chronic activation of the compensatory mechanisms lead to in heart failure?
Clinical signs of volume overload and fluid accumulation, known as congestive heart failure (CHF).
100
What is the term used to describe thickening of the myocardium?
Myocardial hypertrophy
101
What type of hypertrophy is seen with increased circulating blood volume?
Eccentric hypertrophy
102
What is the term used to describe the increased chamber diameter and reduced wall thickness to chamber size ratio?
Dilation
103
Why is it not common to see atrial hypertrophy in cases of volume overload?
Low pressures in diastole require minimal hypertrophy
104
What changes can be predicted using basic principles to make a diagnosis of a particular disease?
Changes in heart structure and function
105
If patients with a particular disease live without treatment, which side of the heart is more likely to fail?
The side of the heart associated with the particular disease
106
How can you calculate heart rate in beats per minute if the paper speed is 25mm/second?
Multiply the number of complexes in 15cm by 10.
107
How can you calculate heart rate in beats per minute if the paper speed is 50mm/second?
Multiply the number of complexes in 15cm by 20.
108
What should be the relationship between P wave and QRS complex in a sinus rhythm?
A sinus rhythm will always have a P wave followed by a QRS complex.
109
What does a P wave followed by no QRS complex indicate?
P waves may not be followed by a QRS in an AV block.
110
How can you check if the relationship between the P wave and QRS wave is normal?
Measure the P-Q interval using the ECG ruler and compare it against the reference interval times.
111
What do upright and narrow complexes in lead II indicate?
Upright and narrow complexes in lead II indicate supraventricular impulses.
112
Which part of the heart has the highest intrinsic rate and acts as the dominant pacemaker?
The sinoatrial node (SAN) has the highest intrinsic rate and acts as the dominant pacemaker.
113
What can hypoxic or damaged cells in the heart do?
Hypoxic or damaged cells can create abnormal pacemakers.
114
What is the significance of pacemaker hierarchy in clinical settings?
Pacemaker hierarchy helps determine the conduction system disorder when the heart rate is low in specific regions.
115
Which lead is typically used to read ECGs?
ECGs are typically read using Lead II.
116
What does the P wave represent in an ECG?
The P wave represents the depolarization of the right and left atrium.
117
What does the P-Q interval represent in an ECG?
The P-Q interval represents the depolarization of the atrioventricular node (AVN).
118
What does the QRS complex represent in an ECG?
The QRS complex represents the depolarization of the ventricles, including the septum, left ventricle, and right ventricle.
119
What does the T wave represent in an ECG?
The T wave represents the repolarization of the ventricles.
120
How can electrolyte imbalances affect the T wave in an ECG?
Prominent T waves may indicate electrolyte imbalances, such as hyperkalemia.
121
What differentiates supraventricular beats from ventricular beats?
Supraventricular beats originate from the sinoatrial node (SAN), have positive P waves in Lead II, and narrow upright QRS-T complexes. Ventricular beats are wider and bizarre in appearance, lack P waves, and are the result of an abnormal pacemaker.
122
What are some clinical signs associated with left-sided congestive heart failure?
Inappetence, lethargy/depression, weakness, exercise intolerance, tachypnea.
123
What is often the first clinical sign in cats with heart disease?
Sudden onset dyspnea.
124
What can cause sudden onset dyspnea in cats with heart disease?
Congestive heart failure or acute pain and paresis/paralysis caused by an arterial thromboembolism.
125
What are some early clinical signs of heart disease in cats?
Lethargy, reduced exercise capability.
126
Do cats with cardiac disease have seizures?
No, but some cats with arrhythmias may develop hypoxic neurological activity that mimics a partial seizure.
127
What should be palpated during a physical examination for cardiac evaluation?
The whole thorax, including high up under the triceps muscles.
128
What does an apical impulse on the right-hand side suggest during palpation?
Cardiac hypertrophy or remodeling, leading to potential diagnostic tests in a patient without a murmur.
129
What pulses should be checked during a physical examination?
Both femoral pulses.
130
What type of pulses may be found in a patient with a patent ductus arteriosus (PDA)?
Hyperkinetic pulses, characterized by a wider pulse and referred to as 'snappy' or 'water hammer' pulses.
131
What should be checked regarding mucous membranes during a physical examination?
Mucous membrane color and capillary refill time (CRT).
132
What is considered a normal capillary refill time (CRT)?
<2 seconds.
133
What should be checked for regarding jugular veins during a physical examination?
Jugular pulsation/distension in the thoracic inlet region.
134
What type of stethoscope is best for auscultating small animal patients?
Stethoscope with a pediatric diaphragm.
135
What should be auscultated first during a cardiac evaluation?
The apical impulse on the left-hand side.
136
What should be assessed during auscultation to identify systole and diastole?
The pulse at the same time as listening.
137
What is the point of maximal intensity of a PDA murmur?
Very high up behind the triceps muscle.
138
Where is the point of maximal intensity of a mitral murmur?
In the left apical region.
139
What could a murmur with a point of maximal intensity at the left heart base indicate?
Pulmonic or aortic stenosis.
140
What should be auscultated over the right heart base?
Some aortic murmurs that may radiate around and across to the right-hand side.
141
What is examined during abdominal ballottement and jugular venous distension?
Evidence of ascites in a dog with right-sided congestive heart failure.
142
What can be mistaken for a large abdomen in dogs with right-sided congestive heart failure?
Evidence of ascites.
143
How is abdominal ballottement performed?
Place palm on one side of abdomen, tap on opposite side to feel for fluid wave.
144
What can be detected by checking for jugular venous distension?
Presence of high pressure in jugular vein is diagnostic of right-sided congestive heart failure.
145
What are the four types of breathing patterns?
1. Restrictive 2. Obstructive 3. Inspiratory 4. Paradoxical
146
Which respiratory pattern indicates a disorder in the pleural space or pulmonary interstitium/alveoli?
Restrictive pattern
147
What does obstructive breathing pattern indicate?
Disease in the lower airways such as chronic bronchitis or asthma (in cats).
148
Which respiratory pattern localizes the problem to the extra-thoracic airways?
Inspiratory pattern
149
What causes paradoxical breathing pattern?
Respiratory fatigue of the diaphragm and intercostal muscles, seen in pleural space disease.
150
How is an ECG generated?
Electrodes are attached to the limbs which detect electrical activity of the heart.
151
What is the purpose of True Leads in an ECG?
They provide three perspectives on the heart's electrical activity.
152
How many electrodes are used to generate a 6-lead ECG?
Four electrodes are used.
153
How are augmented leads created in an ECG?
An imaginary electrode is created by averaging two signals from different electrode pairs.
154
What does the RF-LF lead represent in a 6-lead ECG?
The positive electrode is at the right forelimb.
155
How many augmented leads are there in a 6-lead ECG?
There are three augmented leads.
156
What is the positive electrode position in the LF-LH lead of a 6-lead ECG?
At the left foot (hindlimb).
157
On a DV view, where do veins lie?
Veins lie centrally.
158
On a lateral view, where do veins lie?
Veins lie ventrally.
159
What is the size of the artery and vein expected to be?
They should be of a similar size.
160
What is the maximum width of vessels that should be allowed when they cross the 9th rib?
They should not be wider than the 9th rib.
161
On a lateral view, what part of the artery and vein should have a similar size?
The proximal third of the 4th rib.
162
What should be assessed in the lung fields?
The contrast between the lung fields and the vessels.
163
What does good contrast between the lung fields and vessels indicate?
No lung patterns are present.
164
What does increased radiodensity of the lung fields with a loss of vessel contrast indicate?
Alveolar lung pattern.
165
What can be seen in the normal patient regarding central bronchial markings?
Central bronchial markings can be seen.
166
What do left atrial dilation, pulmonary venous distension, and an alveolar/interstitial lung pattern on radiography imply?
Left-sided congestive heart failure.
167
How can the vertebral heart score be measured?
Using the long and short axis of the heart and counting the vertebrae lengths.
168
What is the first step in measuring the vertebral heart score?
Measure the long axis of the heart on the x-ray.
169
What is the second step in measuring the vertebral heart score?
Measure the short axis of the heart on the x-ray.
170
What should be done with the measurement of the long axis of the heart?
Compare it against the spinal column and count the vertebrae lengths.
171
What should be done with the measurement of the short axis of the heart?
Compare it against the spinal column and count the vertebrae lengths.
172
What is the final step in calculating the vertebral heart score?
Add the two vertebrae lengths together.
173
How can dogs with isolated atrial fibrillation be converted?
Dogs with isolated atrial fibrillation can be converted using pharmaceuticals or by performing electrical cardioversion.
174
What sedation method is not advised for potential cardiac patients during thoracic radiography?
Deep sedation using dexmedetomidine is not advised for potential cardiac patients during thoracic radiography.
175
What is the preferred timing of radiographs for conscious or partially sedated cardiac patients?
Radiographs for conscious or partially sedated cardiac patients should be timed with peak inspiration.
176
What can complicate the review of radiographs in equivocal cases of airway disease or congestive heart failure in cardiac patients?
A mild interstitial pattern may be present in radiographs of cardiac patients, which can complicate the review in equivocal cases.
177
What are the recommended settings for exposure when taking thoracic radiographs?
A high kV and low mAs should be used for short exposure time and minimal blurring of moving intrathoracic structures.
178
How can image blur be reduced in thoracic radiographs?
Using a shorter exposure time can help reduce image blur in thoracic radiographs.
179
What is an indicator of x-ray intensity in radiography?
mAs (milliamperes over time) is an indicator of x-ray intensity in radiography.
180
Why should the mAs be reduced and the kV be increased in thoracic radiography?
Reducing mAs and increasing kV helps to expose x-rays for a short duration while maintaining natural contrast in the thoracic cavity.
181
What is a tip for reviewing chest radiographs using a traditional light box?
Use the hot light function to highlight specific areas of the film after reviewing under bright light.
182
What is the recommended distance between the x-ray generator and the plate/cassette during radiography?
The recommended distance is around 1 meter between the x-ray generator and the plate/cassette.
183
How can image quality be improved for larger chests during thoracic radiography?
Using a grid may help improve image quality for larger chests (e.g., dogs over 12kg).
184
What view should be taken first in three-view chest radiography?
The dorsoventral view (DV) should be taken first in three-view chest radiography.
185
What should be included in the collimation for the dorsoventral view in chest radiography?
The collimation should include the thoracic inlet cranially and the last rib caudally.
186
Why is a three-view chest radiography desirable?
In each lateral view, one lung will undergo atelectasis and not be imaged well.
187
What should be included in the lateral collimation in chest radiography?
The lateral collimation should include the lateral aspects of the ribs.
188
What breed of dogs are commonly affected by dilated cardiomyopathy (DCM)?
Bulldogs, Great Danes, Irish Wolfhounds, Deerhounds, Newfoundland, Boxers
189
What is the prevalence of DCM in dogs above three years old?
It seems to increase dramatically
190
What other heart disease is often confused with DCM in dogs?
Arrhythmogenic right ventricular cardiomyopathy (ARVC)
191
What is the most commonly affected heart disease in cats?
Hypertrophic cardiomyopathy (HCM)
192
What is the prevalence of HCM in cats in large prevalence studies?
1 in 7 cats in a shelter population, but can rise to 1 in 2.5 cats in older age
193
Which cat breed is often affected by HCM?
Maine Coon, Ragdoll, Sphynx, Bengal, British Shorthair, Norwegian Forest, Persian and Birman
194
What genetic marker has been identified for HCM in Maine Coons and Ragdolls?
Myosin-binding protein C3
195
What heart diseases are commonly seen in Dogue de Bordeaux?
Right-sided cardiomyopathy, atrial fibrillation (AF), subaortic stenosis, tricuspid dysplasia
196
What heart condition is French Bulldogs more likely to present with?
Pulmonic stenosis
197
What clinical signs may be associated with heart disease without congestive heart failure in dogs?
Lethargy/depression, syncope, weakness, exercise intolerance, and coughing
198
What clinical signs may be associated with left-sided congestive heart failure in dogs?
Inappetence, lethargy/depression, weakness, exercise intolerance, tachypnoea, and polyuria/polydipsia
199
What clinical signs may be associated with heart disease without congestive heart failure in cats?
Lethargy/depression, syncope, weakness, and exercise intolerance
200
What is the heritability of most cardiac diseases?
Most cardiac diseases, acquired and congenital, are considered to be genetic and therefore heritable.
201
Which breed is known for degenerative mitral valve disease?
Cavalier King Charles spaniel
202
What percentage of Cavalier King Charles spaniels are affected with degenerative mitral valve disease by 10 years old?
100%
203
What breed has become the 'poster child' for dilated cardiomyopathy?
Dobermann pinscher
204
What is the location of the sino-atrial node (SAN)?
Roof of the right atrium
205
Which lead would show a positive deflection for atrial depolarization?
Lead II
206
What is the average direction of conduction in a normal heart?
From the right hand to the right foot
207
What is the purpose of using a 12-lead ECG?
To provide a more complete picture by adding a transverse plane
208
Where is the electrode placed for V1 in the 12-lead ECG?
First right intercostal space
209
Why is a 12-lead ECG rarely indicated over a six-lead recording?
Six-lead ECG is suitable for most arrhythmia diagnoses
210
Where is the sinoatrial node (SAN) located?
Roof of the right atrium
211
What is the role of the atrioventricular node (AVN)?
Carry electrical activity from the atria to the ventricles
212
What prevents the ventricles from being activated by the atria without the control of the AVN?
Atrioventricular fibrous plate
213
What is the association between early treatment and symptom-free period in MVD and DCM?
Early treatment is associated with a longer symptom-free period in MVD and DCM.
214
How can clinically significant mitral valve disease be identified?
All dogs with clinically significant mitral valve disease will have an audible systolic heart murmur which localises to the left apex and radiates dorsally.
215
What is the recommended screening approach for dogs with murmurs?
A more targeted approach is recommended where grade III or louder murmurs are investigated.
216
What challenges are faced in screening for dilated cardiomyopathy (DCM) in dogs?
Screening for DCM is problematic as most patients have no heart murmur and their first sign of heart disease may be dramatic.
217
What are some high-risk breeds for DCM that should undergo annual echocardiography and 24-hour Holter ECG monitoring?
Breeding pedigree dogs considered high-risk, such as Doberman pinscher, Great Dane, Newfoundland, Boxer, Irish Wolfhound, Deerhound, Dogue de Bordeaux, and more should undergo annual echocardiography and 24-hour Holter ECG monitoring.
218
Why is it impractical to perform annual echocardiography and 24-hour Holter ECG monitoring for most pet dogs?
Annual echocardiography and 24-hour Holter ECG monitoring are impractical for most pet dogs.
219
What factors can help identify the highest risk population for DCM?
Combining age and breed can help identify the highest risk population for DCM.
220
How can NT-proBNP be used to detect occult DCM in apparently healthy dogs?
NT-proBNP, a cardiac biomarker increased in response to greater cardiac stress or stretch, may be used to detect occult DCM in apparently healthy dogs.
221
What makes it difficult to use a single cut-off value for NT-proBNP in dogs?
NT-proBNP in dogs has notable variability between breeds, high day-to-day variability, and significant variation between individuals.
222
What are the suggested cut-off values for NT-proBNP in Dobermans and other breeds of dog?
Suggested cut-off values for NT-proBNP in Dobermans and other breeds of dog are 600 pmol/L and 900 pmol/L, respectively.
223
What breed shows that half or more of normal dogs measure >900 pmol/L for NT-proBNP?
Data on breed variability shows that in some breeds, such as Labrador retrievers and Newfoundlands, half or more of normal dogs measure >900 pmol/L.
224
What is the purpose of using echocardiography for screening?
Echocardiography is used for screening to detect cardiac abnormalities in dogs.
225
What is the role of 24-hour Holter ECG monitoring in DCM screening?
24-hour Holter ECG monitoring is used in DCM screening to monitor for evidence of early DCM and ventricular arrhythmias.
226
What is the age range that dogs should be considered for DCM screening?
Dogs of 6-8 years or older should be considered for DCM screening.
227
What is the purpose of using cineloop in imaging?
To allow pausing and reviewing of images from moments ago.
228
Why should cineloops be stored in preference to still 2D images?
Cineloops provide the ability to review images, while 2D images do not.
229
How can cineloops be visually adjusted to visualize high frequency events?
They can be slowed down.
230
In imaging, how should the probe position and heart base be set for the image orientation?
The probe should be at the top and the heart base to the right of the image.
231
What effect does setting the reject filter to low have on image compression?
Lower compression leads to higher contrast compression and more black and white images.
232
Why is having a reject set low suitable for cardiac examinations?
It shows better wall and valve resolution.
233
What happens if the compression is too great in cardiac imaging?
It leads to reduced myocardial tissue image quality.
234
What are the different grey maps used for in cardiac imaging?
They are used to suit different operator preferences and improve blood pool visibility.
235
What does the low velocity (wall) filter ignore when performing Doppler imaging?
It ignores low velocity motion to prevent artefacts from wall and valve motion.
236
What does enabling the persistence setting do in imaging?
It manually reduces frame rate and blurs images together.
237
For which type of imaging is the persistence setting useful?
It is useful for abdominal or tendon imaging.
238
What is the potential downside of zooming in an image?
The image may appear pixelated.
239
How can harmonics improve imaging quality?
Harmonics can reduce artefacts and improve tissue resolution.
240
What is the potential drawback of increasing the frame rate manually?
It may lead to reduced 2D image quality.
241
How can the frame rate be maximized in imaging?
By reducing sector width and reducing post-processing like reject and dynamic range.
242
What does increasing the 'packet sampling size' do in colour Doppler imaging?
It provides finer colour imaging and greater chamber filling at the expense of frame rate.
243
What are common errors in imaging caused by wide sector angle and inappropriate depth?
Low line density, reduced resolution, and lower frame rate.
244
What can inappropriate gain settings lead to in imaging?
Inability to accurately assess Doppler measurements and poor contrast between structures and blood pool.
245
What can excessive 2D gain during colour Doppler studies result in?
Poor assessment of colour flow and under-colouring.
246
What does high colour Doppler gain cause in imaging?
Bleeding of the colour signal over the borders of cardiac structures and over-colouring.
247
What is the effect of having persistence set on or high in imaging?
It leads to blurred image quality and poor definition of colour Doppler.
248
Why is operator experience important in cardiac imaging?
Lack of experience can lead to misinterpretation of normal flow and variations as pathology.
249
What is the consequence of not timing events with simultaneous ECG in imaging?
Normal flow may be over-interpreted and the duration of flow events may be uncertain.
250
Why is it important to look at the heart in echocardiography?
To diagnose cardiac disease based on clinical signs and confirm the cause of symptoms.
251
In which scenario would you screen for disease using echocardiography?
In at-risk dogs for dilated cardiomyopathy (DCM) or those with a family history of DCM or HCM.
252
What purpose does echocardiography serve for asymptomatic murmurs?
To confirm the diagnosis and stage the disease to determine if treatment is necessary.
253
How can echocardiography be used pre-anesthesia or fluid administration?
To assess the heart's condition before undergoing procedures or receiving fluids.
254
How can echo be used to gauge the risk of a procedure for an old cat with chronic kidney disease?
By performing an echocardiogram.
255
What is the recommended position of the patient when performing an echocardiogram from the right-hand side?
Right lateral recumbency.
256
What are the views obtained in the right parasternal long-axis view?
4 chamber and 5 chamber views.
257
What should the left atrium look like in the right parasternal long-axis 4 chamber view?
Angular and hexagonal.
258
What part of the left ventricle should be visible in the right parasternal long-axis 4 chamber view?
The pointed part.
259
What can be visualized in the right parasternal long-axis 5 chamber view?
The left ventricular outflow tract, aortic valve, and beginning of the ascending aorta.
260
How does the left atrium appear in the right parasternal long-axis 5 chamber view?
Small.
261
What is the recommended orientation of the probe to obtain a short axis view?
Rotate the probe 90 degrees anti-clockwise.
262
What is the shape of the left ventricular blood pool in the right parasternal short axis view?
Mushroom-shaped.
263
What should be the symmetry of the right parasternal short axis view?
As symmetrical as possible.
264
What measurements are taken in the right parasternal short axis view?
Functional measurements.
265
What is M mode used for?
To measure fractional shortening.
266
How is the movement of echo structures traced in M mode?
Along a single line of pixels.
267
What valve can be visualized in the right parasternal short-axis view by moving the probe dorsally?
Mitral valve.
268
What is another name for the right parasternal short-axis view of the heart base?
Fish mouth view.
269
What cusps of the aortic valve should be visible in the view just above the mitral valve?
The non-coronary cusp, the right coronary cusp, and the left coronary cusp.
270
How is the left atrial size measured in the view just above the mitral valve?
From the mid-right coronary cusp to the commissure.
271
What is the maximum diameter of the left atrium that is considered normal in this view?
1.5 times the diameter of the aorta.
272
What is the reference for mitral valve disease?
The 2019 ACVIM Consensus Statement on the disease (Keene et al).
273
Which dogs are considered to be at greatest risk of mitral valve disease?
Small breed dogs and atypical breeds like the Border collie, German Shepherd dog, and Labrador retriever.
274
At what age do dogs typically start showing signs of mitral valve disease?
6 years old and older.
275
What is the term for dogs that are 'at risk' of developing mitral valve disease?
Stage A dogs.
276
What is the recommended cut-off for screening DCM in Labradors?
The cut-off in Labradors should be closer to 2000 pmol/L.
277
Why is it difficult to make firm recommendations for screening DCM in breeds other than Dobermans?
There is poor agreement and more data is required before a consensus can be reached.
278
How may family history affect the screening threshold for DCM?
If known affected dogs are present within two or three generations, the threshold may be reduced.
279
What is the current problem with the classification system for feline cardiomyopathy?
It does not account for changes seen as heart disease progresses over time.
280
What are the possible classifications for cardiomyopathy in cats?
Hypertrophic, restrictive, dilated, arrhythmogenic right ventricular, or unclassified cardiomyopathy.
281
How is hypertrophic cardiomyopathy (HCM) defined in cats?
Left ventricular myocardium measures ≥6mm in any 2D view.
282
What are some possible causes to exclude when diagnosing hypertrophic cardiomyopathy (HCM) in cats?
Hyperthyroidism, hypertension, infiltration, acromegaly, Cushing’s disease.
283
How is restrictive cardiomyopathy (RCM) characterized in cats?
Non-hypertrophic, non-dilated left ventricle with normal systolic function.
284
What is the characteristic finding of restrictive inflow pattern in restrictive cardiomyopathy (RCM) in cats?
It can be detected on Doppler interrogation of the mitral valve.
285
How is dilated cardiomyopathy (DCM) defined in cats?
It is characterized by a dilated, non-hypertrophic left ventricle with subnormal systolic function.
286
What are the identifying features of arrhythmogenic right ventricular cardiomyopathy (ARVC) in cats?
Disproportionate right heart dilation, normal appearing left ventricle, and arrhythmias on ECG.
287
What does unclassified cardiomyopathy (UCM) refer to in cats?
It includes cases that don't fit into any of the other classifications.
288
How can intracardiac thrombi form in cats with heart disease?
When the left atrium is enlarged and hypofunctional, it can lead to intracardiac thrombosis and arterial thromboembolism.
289
What is the estimated overall prevalence of cardiomyopathy in cats?
Around 15% with a male predisposition.
290
What was the prevalence of cardiomyopathy in cats at different age groups according to the CatScan study?
The prevalence increased from around 5% to over 30% between the ages of 1- and 9-years-old.
291
How common are heart murmurs in cats according to the CatScan study?
41% of all cats had heart murmurs.
292
Are heart murmurs a good way to diagnose heart disease in cats?
No, they are less useful than making the decision based on a coin toss.
293
What percentage of cats with heart murmurs had heart disease in the different age groups?
18% in juvenile cats, 25% in young adults, 30% in middle-aged cats, and 43% in older cats.
294
What is considered the gold-standard test for diagnosing heart disease in cats?
Echocardiography.
295
What is a nutritional secondary DCM?
A heart disease in dogs that may be caused by diets lacking certain nutrients.
296
What evidence is there for the development of nutritional secondary DCM in dogs?
There is anecdotal evidence, but no convincing published evidence.
297
What is the concern regarding grain-free diets and nutritional secondary DCM?
The large quantities of legumes or pulses used to balance the nutrition may cause taurine deficiency.
298
How is nutritional secondary DCM currently managed in dogs?
By obtaining a full diet history and switching to a non-grain-free diet.
299
What should clients who don't wish to feed a commercial diet do?
They should see a veterinary nutritionist for balanced home-cooked raw diet recipes.
300
What is arrhythmogenic right ventricular cardiomyopathy (ARVC)?
A heart disease that affects the right ventricle, causing fibro-fatty infiltration and arrhythmias.
301
Which breed of dogs are considered predisposed to ARVC?
Boxer dogs.
302
What are the three forms or stages of ARVC?
Class I, Class II, and Class III.
303
How is ARVC similar to DCM?
For some breeds, both diseases may be diagnosed interchangeably.
304
What is the striatin mutation associated with ARVC in Boxer dogs?
A mutation in the Boxer dog that may contribute to the development of ARVC.
305
What is the proposed effect of the striatin mutation on ARVC in Boxer dogs?
Having two copies of the mutated gene may worsen the disease.
306
How should dogs with ARVC be managed?
Managed for systolic dysfunction, treated for heart failure signs, screened for arrhythmias.
307
What is the importance of the pathological diagnosis for dogs with ARVC?
The actual diagnosis is not important, as the treatment is focused on symptoms.
308
Why is screening for MVD and DCM important?
To provide owners with expectations, monitor the disease, and plan future procedures.
309
What considerations should be made for routine anaesthesia in dogs with occult heart disease?
Owners should be advised about potential risks and necessary precautions.
310
What factors are associated with an increased likelihood of heart disease in a cat with a heart murmur?
Clinical signs, other auscultatory abnormalities, jugular pulsation, loud heart murmur, being male, age, and body condition score.
311
What are the clinical signs associated with heart disease in a cat with a heart murmur?
Respiratory signs, syncope or episodic weakness, lethargy, and reduced appetite.
312
What are some other auscultatory abnormalities associated with heart disease in cats?
Presence of a gallop sound or an arrhythmia.
313
What does jugular pulsation indicate in cats with a heart murmur?
High right atrial pressure.
314
What grade of heart murmur indicates an increased probability of heart disease on echo?
Grade 3 or above.
315
What is the significance of being male in relation to cardiomyopathy in cats?
Boys appear to get cardiomyopathy younger or have a more rapidly progressive form.
316
Which age group of cats more commonly gets heart disease?
Older cats.
317
What body condition score indicates a greater likelihood of heart disease in cats?
6 out of 9 or above.
318
What tests can help detect occult cardiomyopathy in cats?
Cardiac biomarkers, such as NT-proBNP.
319
What is the cut-off value for feline NT-proBNP to detect asymptomatic heart disease?
Approximately 100 pmol/L.
320
What does an abnormal result in the feline NT-proBNP test indicate?
Further cardiac imaging is required.
321
What is the negative predictive value of NT-proBNP tests in cats?
High, indicating a normal heart or clinically insignificant cardiomyopathy.
322
When should at-risk cats be screened annually for heart disease?
If the first NT-proBNP test is normal.
323
What should be considered when interpreting NT-proBNP measurements in cats?
Day-to-day variability and baseline values.
324
What is arterial thromboembolism in cats?
Condition associated with high morbidity and mortality, commonly involving a thrombus in a limb.
325
Where does the thrombus in arterial thromboembolism usually originate in cats?
Left side of the heart.
326
What signs are associated with limb arterial thromboembolism in cats?
Loss of peripheral pulses, tissue pallor, lower motor neuron signs, and cool extremities.
327
What is the relationship between high frequency ultrasound and image quality?
High frequency ultrasound has better 2D image quality and detail.
328
Which animals are high frequency ultrasound probes suitable for?
High frequency ultrasound is suitable for smaller animals like cats.
329
What is the advantage of high frequency ultrasound probes?
High frequency probes have a smaller footprint and image well between the ribs in a cat.
330
When should lower frequencies be used in ultrasound imaging?
Lower frequencies should be used for greater imaging depths or Doppler studies.
331
What is the compromise when using different transducers in a study?
A compromise between image quality and a diagnostic study must be sought.
332
What should the operator aim for in terms of ultrasound frequency?
The operator should aim for the highest frequency that provides sufficient tissue resolution.
333
What is the importance of temporal resolution in echocardiography?
Temporal resolution is important for detecting subtle changes and measuring cardiac function.
334
What can reduce the frame rate in echocardiography imaging?
Imaging at greater sector widths or using color Doppler can reduce the frame rate.
335
What should be done to interpret the timing of events during the cardiac cycle?
Using a simultaneous ECG is vital for interpreting the timing of events.
336
What is the effect of a slow frame rate in echocardiography?
Systolic and diastolic events can appear to occur at the same time.
337
What can be done to maintain high temporal resolution when storing images?
Reviewing studies prior to compression and storage can help maintain temporal resolution.
338
What are some common machine settings for echocardiography?
Mode (2D, M-mode, Doppler), gain, time gain compensation, depth, width, focus point.
339
What does the time gain compensation setting adjust?
Time gain compensation adjusts image brightness at various depths.
340
How should the depth setting be adjusted for optimal imaging?
Maximize the size of the heart within the screen.
341
What is the effect of reducing the width or sector angle?
Narrower sectors provide faster frame rates.
342
What should be considered when selecting the focus point?
Positioning the focus point at the appropriate depth has a significant effect on image quality.
343
What is the prognosis of cats presenting with a first episode of acute clinical signs?
No prospective studies have reported the outcome.
344
What factors were associated with a decreased rate of survival to discharge in cats with ATE?
Hypothermia, ≥2 affected limbs, absence of motor function, hyperphosphataemia, and bradycardia.
345
What factors were associated with death or euthanasia before discharge in cats with ATE?
Hypothermia and ≥2 affected limbs.
346
What is the suggested survival time after discharge for cats with congestive heart failure (CHF) and ATE?
Shorter than cats without CHF.
347
What is the importance of assessing rectal temperature at presentation of ATE?
Lower rectal temperature predicts higher likelihood of death at 24h and before 7 days.
348
What treatment is associated with an increased likelihood of survival to 7 days in cats with ATE?
Treatment with an anti-platelet agent (aspirin, clopidogrel, or both drugs).
349
What is the estimated survival rate to 7 days for cats treated for ATE in general practice?
55%.
350
What is the estimated 1 year survival rate for cats alive at 1 week after an acute ATE episode?
20%.
351
What is the approach to the treatment of ATE in cats?
Immediate analgesia and anti-platelet agents.
352
What is the efficacy of anti-platelet treatment in preventing ATE recurrence?
Clopidogrel has an average recurrence interval of 442 days, compared to 192 days with aspirin.
353
What are the stages of Mitral Valve Disease (MVD)?
Stage A, Stage B1, Stage B2, Stage C, Stage D
354
What is the characteristic of Stage B1 MVD?
Characteristic heart murmur but no cardiac remodeling on imaging
355
How can Stage B2 MVD be identified?
Cardiomegaly on imaging without overt clinical signs
356
What are the clinical signs of Stage C MVD?
Current or previous signs of congestive heart failure
357
What is the treatment for Stage D MVD?
Standard therapy including furosemide, pimobendan, ACE-inhibitor, and spironolactone
358
How is the significance of MVD determined?
Detectable cardiomegaly on echocardiography or thoracic radiography
359
What are the criteria for considering a dog in Stage B2 of MVD?
Left atrial to aortic root ratio >1.6 and left ventricular internal diastolic diameter >1.7 normalized for body weight
360
What is considered significant cardiomegaly in radiographs?
Vertebral heart scale >11.5
361
What is the benefit of pre-clinical treatment in MVD?
Prolongs time before developing signs of heart failure, as shown in the EPIC trial
362
What are the two common cardiomyopathies in dogs?
Dilated cardiomyopathy (DCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC)
363
What is the definition of DCM?
Dilation of the LV and reduced systolic function in the absence of other identifiable causes
364
What is the consequence of reduced systolic function in DCM?
Activation of neurohormonal compensation and mitral regurgitation
365
What is the term used for the long pre-clinical course of DCM?
Occult DCM
366
Which breed of dog benefits from treatment with pimobendan for occult DCM?
Dobermans
367
What are the breed differences in the disease course of DCM?
Aggressive disease with frequent ventricular arrhythmias and sudden death in Dobermans, Boxers, and Great Danes, slower progression with atrial fibrillation and lower incidence of sudden death in Newfoundlands and Irish Wolfhounds
368
How can the severity of arrhythmias in DCM be evaluated?
Using ambulatory Holter ECG recording
369
What is recommended as part of routine anesthesia planning in dogs with DCM?
Ambulatory Holter ECG recording
370
What is the optimal patient position for echocardiography?
Lateral recumbency
371
What are some potential restraints for echocardiography?
Lateral recumbency, sternal position, standing position
372
What can be done to minimize air artefacts during echocardiography?
Position the probe beneath the patient so that the dependent lung becomes less aerated
373
What should one consider when choosing an ultrasound machine for performing echocardiography?
Not all ultrasound machines have suitable pre-sets, some may be more appropriate for abdominal imaging than echo, higher quality Doppler echo is generally only available on more expensive machines
374
Why is understanding machine settings and fine tuning important during echocardiography?
To obtain the best images possible for the patients being scanned
375
What are the ideal transducers for cardiac imaging?
Phased array probes
376
How long do most Holter ECGs record for?
2-3 days
377
What type of data is recorded by a Holter ECG?
Digital data in 3 leads
378
What is the function of an implantable loop recorder?
To continuously record ECG and store short single lead traces
379
Where is an implantable loop recorder placed?
Subcutaneously on the left thorax
380
How long can an implantable loop recorder store ECG traces?
Several minutes long loop of storage
381
When are ECG traces stored by an implantable loop recorder?
When heart rate is detected at a particular programmed level or when the owner activates the device during an episode of collapse
382
What is the battery life of an implantable loop recorder?
Up to 3 years
383
What animals have implantable loop recorders been used in?
Dogs, cats, and horses
384
What is the novel external patch device used for?
Recording ECG for up to one week
385
Is the accuracy of external patch devices validated?
No, validation data has not been published yet.
386
What condition is often referred to as 'vaso-vagal syncope'?
Neurocardiogenic syncope
387
How is the diagnosis of neurocardiogenic syncope made?
By excluding other diagnoses and capturing an ECG during an episode of syncope
388
Do most dogs outgrow neurocardiogenic syncope?
Yes, most dogs grow out of the disorder in youth
389
What are some possible causes of syncope?
Diseases of cardiovascular and respiratory systems, reflex-mediated causes, and metabolic diseases.
390
What are some differential diagnoses for syncope?
Anaemia, orthopaedic disease, hypotension, and chronic hypoglycaemia.
391
What tests can be performed for diagnostic investigation of syncope?
History and video recording, physical examination, blood tests, ECG, echocardiography, thoracic imaging, and 24h Holter ECG.
392
What are some characteristics of movement disorders?
Episodic problems, breed-related, self-limiting, and can impact quality of life.
393
What are some potential causes of syncope in cardiovascular system?
Arrhythmia, obstructed cardiac output, obstructed venous return, intra-cardiac right-to-left shunt, and pulmonary hypertension.
394
What are some potential metabolic causes of syncope?
Insulinoma-associated hypoglycemia and phaeochromocytoma-associated hypertension.
395
What is an example of reflex-mediated cause of syncope?
Neurocardiogenic or 'vaso-vagal' syncope.
396
What is misrepresentation in differential diagnoses for syncope?
Considering chronic hypotension or hypoglycemia as the cause of syncope.
397
What factors should be considered when determining the cause of syncope?
Rapid reduction in cerebral blood flow, blood pressure, oxygenation, or glucose provision.
398
What are some potential causes of syncope in respiratory system?
Lungworm infection and severe tracheal collapse.
399
What are some potential causes of syncope in metabolic disorders?
Anaemia, acute hemorrhage, hypoglycemia, hypotension, and hypertension.
400
When does an episode of true syncope occur?
When hypotension or hypoglycemia occurs rapidly and transiently, or if exercise-related hemorrhage occurs.
401
What are some diagnostic investigations for syncope?
History and video recording, physical examination, non-invasive blood pressure measurement, blood tests, ECG, echocardiography, thoracic imaging, and 24h Holter ECG.
402
What are some key considerations when evaluating movement disorders?
Frequency and duration of episodes, breed-relatedness, self-limiting nature, and impact on quality of life.
403
What should be determined during a collapse episode history?
Consciousness of the patient and any change in behavior before and after the episode.
404
What are some characteristics of cardiogenic causes of collapse?
Usually occur after exertion, short-lived, no change in behavior, and episodic loss of consciousness.
405
What is important to ask during a collapse episode history?
Whether the patient was responsive or not, rather than if they were conscious.
406
What does cyanotic mucous membranes indicate during a collapse episode?
Classic appearance of an animal with cardiogenic syncope.
407
How can bacterial pericarditis be detected?
Bacterial pericarditis can often be suspected based on its aroma alone.
408
What is the characteristic sign of pericardial effusion secondary to right-sided heart failure?
Pericardial effusion secondary to right-sided heart failure is often accompanied by a grossly remodelled right heart with right atrial dilation.
409
Why can't cardiac tamponade occur in cases of pericardial effusion secondary to right-sided heart failure?
Cardiac tamponade cannot occur because the elevated right atrial pressure drives the effusion, preventing collapse of the right atrium on echo.
410
How do septic pericardial effusions differ from other types?
Septic pericardial effusions often have the gross appearance of pus and a recognizable smell.
411
Which dog breeds are often at risk of migrating foreign bodies leading to septic pericarditis?
Springer Spaniels and Labrador Retrievers are commonly at risk of migrating foreign bodies leading to septic pericarditis.
412
What antibiotics are usually used as empirical treatment for septic pericarditis?
Amoxicillin-clavulanic acid with metronidazole is commonly used as empirical antibiotics for septic pericarditis.
413
Why should all patients with a previous diagnosis of septic pericarditis undergo sub-total pericardiectomy?
Previous inflammatory changes predispose to the development of constrictive pericarditis.
414
How can pulmonary hypertension be defined?
Pulmonary hypertension is defined as pulmonary arterial pressure (PAP) >35mmHg.
415
What is the primary function of the pulmonary arteries?
The primary function of the pulmonary arteries is to perfuse oxygenated regions of the lung and re-oxygenate blood.
416
Why does vasoconstriction occur in response to hypoventilation and/or hypoxia in the pulmonary vasculature?
Vasoconstriction occurs in response to hypoventilation and/or hypoxia to ensure proper oxygenation of blood.
417
What happens to pulmonary vessels in the face of increased flow?
Pulmonary vessels vasoconstrict in the face of increased flow to prevent the development of pulmonary edema or capillary damage.
418
How can pulmonary hypertension be diagnosed?
Pulmonary hypertension can be diagnosed by direct measurement using a catheter placed in the pulmonary artery or right ventricle.
419
How is pulmonary hypertension classified based on pulmonary arterial pressure (PAP)?
Pulmonary hypertension can be classified as mild (>35mmHg), moderate (50-80mmHg), or severe (>80mmHg).
420
What is the most common cardiac tumor?
The most common cardiac tumor is lymphoma.
421
What is the commonest cause of cardiac tamponade?
The commonest cause of cardiac tamponade is lymphoma, except in young, pedigree cats where FIP is common.
422
Are other forms of cardiac neoplasia common or rare in comparison with lymphoma?
Other forms of cardiac neoplasia are rare in comparison with lymphoma.
423
In cats with pericardial fluid on echo, what is the most common cause of acute or severe heart failure?
In cats with pericardial fluid on echo, the most common cause of acute or severe heart failure is cardiomyopathy.
424
Why is diuretic treatment contraindicated in dogs with cardiac tamponade?
Diuretic treatment is contraindicated in dogs with cardiac tamponade because it may reduce their already poor cardiac output.
425
What is the position and sedation protocol for pericardiocentesis?
The patient is positioned in left lateral recumbency and sedated with midazolam and butorphanol.
426
How should the skin be prepared before pericardiocentesis?
The skin should be aseptically prepared with suitable contact time.
427
What is the purpose of placing an ECG during pericardiocentesis?
The ECG is for continuous monitoring during the procedure.
428
What analgesia is recommended for pericardiocentesis?
Lidocaine 2% solution is recommended for analgesia.
429
How should the clinician prepare for pericardiocentesis?
The clinician should wear sterile gloves and set up a sterile field with necessary equipment.
430
How is access to the pericardium gained during pericardiocentesis?
Access is gained by making a small stab incision and advancing an over-the-needle catheter towards the heart.
431
What should be done after the catheter is advanced into the pericardial space?
The guidewire should be advanced to the dependent surface of the heart.
432
How is the chest tube advanced into the pericardium?
The chest tube is advanced over the guidewire with gentle rotation to facilitate advancement.
433
What should be done after the chest tube is in position?
The guidewire can be withdrawn and the three-way tap attached to the tube for drainage.
434
What samples should be obtained during pericardiocentesis?
Pericardial fluid should be drained for cytology and microbiological culture samples.
435
How should drainage be performed during pericardiocentesis?
Drain as much pericardial fluid as possible without putting negative pressure on the epicardium.
436
What is the formula to calculate the pressure gradient between pulmonary artery and right ventricle?
Pressure gradient = 4 x (maximum velocity)^2
437
What are the secondary changes that can assist in the diagnosis of pulmonary hypertension?
Right ventricular hypertrophy, flattening of interventricular septum, right ventricular systolic dysfunction, pulmonary artery wider than aorta, reduced left heart filling, caudal vena cava enlargement, right atrial dilation
438
How can a patient be classified based on the number of anatomic sites affected and Doppler measurements?
As low, intermediate, or high risk of pulmonary hypertension
439
What are the criteria for assessing animals with possible pulmonary hypertension?
Number of different anatomic sites of echo signs and peak tricuspid regurgitation velocity
440
What are the echocardiographic probability criteria for diagnosing pulmonary hypertension in dogs?
Low probability: < 3 or not measurable peak tricuspid regurgitation velocity; Intermediate probability: 3.0 to 3.4 peak tricuspid regurgitation velocity and 0 or 1 anatomic site; High probability: > 3.4 peak tricuspid regurgitation velocity and > 1 anatomic site
441
What are the radiographic signs of pulmonary hypertension?
Wider cardiac silhouette than two-thirds of the thoracic width, large right heart ('reverse D' shape), wide pulmonary arteries, large amount of sternal contact, right ventricular hypertrophy
442
What is the primary aim of acute treatment for pulmonary hypertension?
Vasodilation
443
What is a potent pulmonary vasodilator that can be used in the acute treatment of pulmonary hypertension?
Oxygen therapy
444
What is the primary medical treatment for pulmonary hypertension?
Sildenafil citrate, a phosphodiesterase 5a (PDE-5a) inhibitor
445
What is the starting dose of sildenafil for treating pulmonary hypertension?
1-2mg/kg q8 hours
446
How should monitoring of pulmonary hypertension be done?
Through clinical signs such as reduction in frequency and severity of syncope, respiratory rate and effort, and exercise capability
447
What are some possible causes of gait abnormalities?
Neurogenic origin or a movement disorder.
448
What signs may be present in an animal with cerebral hypoxia caused by pulmonary hypertension?
Opisthotonos, forelimb rigidity, twitches, vocalising, limb paddling, loss of consciousness.
449
How does sick sinus syndrome often present?
Episodic collapse, weakness, and syncope.
450
What can cause a patient with Sick Sinus Syndrome to lose consciousness?
An 8-10 second pause on an ECG.
451
How is Sick Sinus Syndrome treated?
With the implantation of a pacemaker.
452
What diagnostic tool is vital to get a diagnosis in suspected cases of cardiogenic collapse?
An ambulatory ECG.
453
What is the commonest congenital heart disease?
Congenital 'dysplasia' of valves.
454
Which two regions of stenosis are associated with pressure overload of the right and left ventricles?
Pulmonic valve (pulmonic stenosis, PS) and the subaortic region of the left ventricular outflow tract (subaortic stenosis, SAS).
455
What can ventricular arrhythmias be caused by in cases of valve stenosis?
Myocardial hypoxia and fibrosis.
456
What are the treatment options for valve stenosis?
Medical management with atenolol and minimally invasive balloon dilation via interventional cardiology.
457
What can cause a sudden onset of tachyarrhythmia at exercise in dogs?
Ventricular tachycardia.
458
What clinical signs may be seen in dogs with prolonged tachyarrhythmias?
Weakness, depression, lethargy, and signs of right-sided heart failure.
459
What clinical signs may be seen in dogs with bradyarrhythmias?
Syncope and collapse events, lethargy, and excessive panting.
460
What types of dogs are heavily predisposed to both Subaortic Stenosis (SAS) and Pulmonic Stenosis (PS)?
Brachycephalic dogs, especially Bulldog/Boxer types.
461
What test offers a definitive diagnosis for valve stenosis?
Echocardiography.
462
What signs may be present in dogs with bradyarrhythmias?
Lethargy and excessive panting.
463
What is the most common congenital heart disease?
Congenital 'dysplasia' of valves.
464
What is the syndrome of clinical signs of right-sided heart failure caused by pericardial effusion?
Cardiac tamponade
465
What causes the clinical signs of cardiac tamponade?
Intra-pericardial pressure and inability of the right heart to fill properly
466
What determines the volume of pericardial fluid at which cardiac tamponade occurs?
Rate at which the fluid accumulates
467
What is seen initially as ascites in cases of cardiac tamponade?
Tissue edema caused by the rise in hydrostatic pressure in the vessels behind the heart
468
What is the most likely cause of rapid fluid accumulation in cardiac tamponade?
Haemorrhage
469
What are the typical history findings in cases of pericardial effusion?
Lethargy, depression, exercise intolerance, prolonged recovery from exertion, abdominal distension, polydipsia, gastrointestinal signs, syncope/collapse/weakness
470
What are the physical examination findings in cases of pericardial effusion?
Abdominal distension, organomegaly, fluid thrill on ballottement, jugular distension and pulsation, poor pulse quality/pulsus paradoxus, muffled heart sounds/pericardial friction rubs
471
What is pulsus paradoxus and what is it pathognomonic of?
Pulse quality reduction or absence during inspiration, pathognomonic of cardiac tamponade
472
What blood tests are critical for diagnosing pericardial effusion?
Effusion cytology and fluid analysis after drainage to exclude exfoliative neoplasia
473
What can elevated ALT and ALKP in blood tests indicate in cases of pericardial effusion?
Hepatic congestion
474
Who is the module developer for Small Animal Medicine Distance Learning Module 13: Cardiovascular Medicine II?
Dr Kieran Borgeat
475
Who are the module tutors for Small Animal Medicine Distance Learning Module 13: Cardiovascular Medicine II?
Dr Brad Gavaghan and Dr Fiona Meyers
476
What are the learning objectives of this module?
1. Understand different disorders that can be presented by an owner as 'collapse'. 2. Compare and contrast the features of syncope and seizures. 3. Have an awareness of different options for ambulatory ECG and when to recommend their use. 4. Understand the pathophysiology of pericardial effusions in dogs, and how to detect them using key physical examination findings. 5. Describe the differential diagnoses for pericardial effusion in dogs. 6. Use an appropriate technique for pericardiocentesis in dogs and understand when drainage is indicated. 7. Understand which aspects of pulmonary vascular physiology can become maladaptive and lead to pulmonary hypertension. 8. Identify cases in practice which may be suffering from pulmonary hypertension, and understand how to make a diagnosis. 9. Consider treatment of pulmonary hypertension in different disease contexts, and understand what outcomes can be expected.
477
What is syncope?
Syncope is a transient loss of consciousness and postural tone caused by reduced cerebral blood flow.
478
What are the key elements of syncope?
Transience, unconsciousness, and falling over.
479
What are typical features of syncope that contrast with a seizure?
Association with exercise/excitement, no pre-episode abnormalities, falling over with flaccid posture, unresponsiveness with eyes open or glazed, rapid recovery to normal within 1-2 minutes, and no abnormal behavior later in the day.
480
What may be observed during syncope episodes?
Opisthotonus, limb rigidity or paddling, urination or defecation, or faciomotor activity in cats with arrhythmias.
481
What findings suggest an episode is not true syncope?
Jaw champing, salivation, nystagmus, and pre-episodic abnormalities are not typical of true syncope.
482
What is Sick Sinus Syndrome?
It is a diagnosis made when runs of tachycardia, episodes of bradycardia, long pauses and occasional AV blocks are present in a dog with syncope or episodic weakness.
483
How is pulmonary hypertension (PH) diagnosed in veterinary patients?
It is best diagnosed using Doppler echocardiography to estimate pulmonary artery pressure in systole.
484
What are the common causes of pulmonary hypertension in veterinary patients?
Chronic left-sided heart failure, severe respiratory disease, infection with Angiostrongylus vasorum, and congenital heart disease.
485
What is the treatment for pulmonary hypertension in veterinary patients?
Treatment with sildenafil, a pulmonary vasodilator through phosphodiesterase-V inhibition, is prescribed to help control clinical signs.
486
What are the possible mechanisms of syncope in pulmonary hypertension?
It is unclear but could be related to reduced cardiac output during exercise or activation of mechano-receptor mediated syncope.
487
What is the effect of right-to-left shunting in congenital heart disease?
It leads to deoxygenated blood entering systemic circulation.
488
How can a right-to-left shunt in dogs lead to syncope?
Cerebral hypoxemia itself can lead to syncope, and chronic hypoxemia can cause erythrocytosis and hyperviscosity which contribute to sluggish cerebral flow.
489
What is the clinical presentation of dogs with a right-to-left patent ductus arteriosus (PDA)?
They present with hindlimb weakness and caudal body cyanosis during exercise.
490
What should be measured in dogs with a history of exercise-induced signs?
PCV (packed cell volume) should be measured, and if erythrocytosis is present, echocardiography is a rational diagnostic step.
491
What is the recommended diagnostic step for dogs without obvious causes of collapse on echocardiography?
They should undergo further diagnostic investigations to identify potential underlying cardiac causes.
492
What is one method to assess PAP non-invasively?
Performing echocardiographic measurements based on Doppler measurements.
493
Do echocardiographic methods accurately estimate PAP?
No, they tend to under-estimate PAP.
494
What do Doppler estimates of PA pressure not always reflect?
Clinical improvements in dogs treated for PH.
495
Why are echo estimates of PA pressure still useful despite being imperfect?
They are non-invasive and useful enough to make clinical decisions.
496
What are the six classes of pulmonary arterial hypertension?
1. Associated with congenital L>R shunting disease, 2. Secondary to left heart disease, 3. Secondary to lung diseases or hypoxia, 4. Thrombotic causes, 5. Parasitic causes, 6. Unclear/multifactorial mechanisms.
497
What are some examples of diseases associated with secondary pulmonary hypertension?
Mitral valve disease, left ventricular systolic dysfunction, left ventricular diastolic dysfunction, and congenital diseases affecting the left heart.
498
What are the historical features strongly associated with pulmonary hypertension?
Syncope, increased respiratory effort at rest, activity terminated by dyspnea, and right-sided congestive heart failure.
499
What are some clinical examination findings associated with pulmonary hypertension?
Loud, right-sided heart murmur, split S2 sound, jugular distension, pulsation, ascites, and signs of lung disease.
500
How is pulmonary arterial pressure estimated using echocardiography?
Tricuspid and/or pulmonic regurgitation velocity measurements are used to estimate PAP.
