Module 15 Wk 1 Flashcards
(Acquired cardiac diseases in dogs - Valvular problems and Cardiomyopathies)
What is concentric hypertrophy?
Pressure overload where wall grows thicker towards center of heart.
What is eccentric hypertrophy?
Volume overload where wall of heart grows towards the outside
What is MMVD?
Myxomatous mitral valve disease
What kinds of dogs is Myxomatous mitral valve disease most common in?
- Highest prevalence in medium size breeds.
- Older dogs
- Mostly male
- CKCS
Describe what Myxomatous mitral valve disease is?
Changes in the cellular constituents as well as the intercellular matrix of the valve apparatus
In Myxomatous mitral valve disease, what do the changes to the valve lead to?
Irregularity of the valves leads to an inability to close properly and prolapse of LA so Insufficiency/Regurgitation
What are consequences of Myxomatous mitral valve disease?
- There is an increase in left atrial pressure, which leads to left-sided CHF.
The left ventricle is experiencing a volume overload due to the LA accommodating more blood, so the LV has to get bigger to push more blood forward. - Due to pressure being high on the left, it may cause pulmonary hypertension on the right and lead to right-sided CHF as the arteries constrict.
What are the different stages of heart disease?
Stage A: dogs at risk for developing heart disease but no clinical signs or structural changes. Predisposed.
Stage B: structural changes are present
- B1: Clear valvular insufficiency, but no clear cardiac remodelling is present. Valve leaking but heart is not big yet as heart not noticed it yet.
- B2: Clear valvular and cardiac remodelling present. Heart bigger as has noticed it
Stage C: Current or past clinical signs of heart failure. Developed oedema.
Stage D: End-stage, refractory to treatment
T/F a dogs with Myxomatous mitral valve disease (MMVD) is commonly asymptomatic?
True
If there is clinical symptoms what would they be?
- will have a cough is severe L CHF
- dyspnoea
- syncope
- Exercise Intolerance
What should you hear when auscultating a dog with Mitral valve disease?
- Left-sided apical systolic murmur!
- Right side? If very loud or concomitant tricuspid regurgitation
What would you see on radiographs of a dog with mitral valve disease?
congested pulmonary vein, increased left atrial size, elevation of trachea and compression of the left principal bronchus
Cowboy legs tell you L atrium get bigge!!!!!!!
What diagnostic tool confirms mitral valve disease and why?
Echocardiography confirms disease! Mitral valve changes and dilatation of left atrium/ventricle
T/F with mitral valve disease NTproBNP and cradiac troponin I will both increase?
True
What are your treatment opyions for the different stages of mitral valve disease?
Stage A, B1: nothing
Stage B2: Pimobendan
Stage C: Pimobendan + Diuretics (clinical signs)
What does DCM stand for?
Dilated cardiomyopathy
What is dilated cardiomyopathy?
It is where the muscle cannot pump therefore the heart has to try compensate by stacking more muscles in series leading to volume overload.
What kind of dogs does DCM effect the most?
It mostly affects large/giant breeds of dogs that are often middle-aged/older. Mostly males over females.
What is the difference between primary and secondary DCM?
Primary is when you inherit DCM, whereas secondary is where it mimics DCM, but the heart muscle is not the problem.
What sort of things could cause secondary DCM?
- Arrhythmia- induced
- Metabolic; diabetes, systemic hypertension, hypothyroidism, acromegaly and pheochromocytoma
- Drugs and toxins; chemotherapeutic agents, catecholamines
- Nutrition
- Myocarditis (inflammatory); infectious and non-infectious diseases
Describe DCM with big words babes
The Myocardium is sick leading to systolic Dysfunction. This causes low cardiac output (exercise intolerance) and Cardiac Remodelling stimulus (left eccentric hypertrophy). Resulting in Left (+ right) sided congestive heart failure.
ANDDDD a Sick heart = Arrhythmias = Syncope/Sudden Death.
What would a dogs history be if the had DCM?
- Asymptomatic (occult)
- Exercise intolerance
- Cough (acute congestive heart failure)
- Tachypnoea, Dyspnoea
- Right sided problem: Pleural effusion, ascites
- Syncope
On a clinical exam of a dog with DCM what would you find?
- A low grade murmur or none
- Arrhythmias
- Weak pulse
- Tachycardia
- Prolonged capillary refill time
- Left sided CHF: Dyspnoea
- Right sided CHF: Ascites
How should you treat a dog with DCM?
- radiographs arent to slay at helping
- biomarkers again are not super slay but can hint to cardiac probs
- ECG good to see arrhythmias as the arrive before cardiac remodelling
- Treat with pimobenden
What is the survival time once clinical signs of DCM are present in dobermanns?
3-4months
What does ARVC mean?
Arrhythmogenic (right ventricular) cardiomyopathy
What is the pathophysiology of Arrhythmogenic (right ventricular) cardiomyopathy?
Fatty or fibrofatty replacement of the myocardial tissue, mainly affecting the right ventricle leading to eccentric volume overload = DCM Phenotype
What is HCM?
Hypertophic cardiomyopathy is a pressure overload phenotype causing concentric hypertrophy - rare in doggos and usually asymptomatic
(Clinical presentation and diagnostic considerations of the small animal cardiac patient)
Describe normal heart
- The ventricles begin to contract after they have been electrically activated which raises the pressure inside the ventricular chambers above that in the atria. The mitral and tricuspid atrioventricular valves close and tense
S1 provides an audible signal of the beginning of mechanical ventricular systole - At the end of systole the ventricular pressures fall and when pressures fall below the pressures in the aorta and pulmonary artery, the aortic and pulmonic valves close. S2 is subdivided into an aortic component (A2) and a pulmonic component (P2) and provides an audible marker for the end of systole and the beginning of diastole
- The normal cadence of S1 and S2 (lub-dup, where “lub” is S1 and “dup” is S2) is identified first—at the cardiac apex, S1 should normally be louder, longer, and lower pitched than S2.
S3 and S4 is normally made by the sound of the blood moving between chambers, however this is normally not heard in SA
bro idek come back to this
what are the 5 qualities of a heart murmour?
- Timing
- Intensity
- Location
- Quality: Pleateau, Crescendo-Decrescedo, Decrescendo, Continous or Machinery
- Pitch: Frequency (high/low, musical)
What is the timing of a murmur determined by?
By the phase of the cardiac cycle:
- Systolic (S1 to S2)
- Diastolic (S2 to S1)
- Continuous (machinery)
What is intensity of the murmour?
How loud it it
What are the 3 different shapes murmours can be?
- Regurgitant (also called plateau-shaped or rectangular)
- Ejection (crescendo-decrescendo or diamond-shaped)
- Blowing (decrescendo)
Describe a sinus rhythm
- Regular rhythm, characterized by a monotonous S1-S2 cadence.
- Approximately 60 – 160 bpm in dogs, 140 – 220 in cats.
Describe a sinus arrhythmia
A reg irreg pattern associated with breathing. normal or slow HR
What is atrial fibrillation?
Generally rapid irregularly irregular rhythm. atrium going cra cra
What are normal lung sounds created by?
The turbulent movement of air in the tracheobronchial tree in large airways transmits to the chest wall.
When do you lung sounds are abnormal?
Louder
What are the 3 categories of abnormal adventitial lung sounds?
- Crackles = Fine or Coarse
- Wheezes
- Ronchi
Describe fine crackles
They have a short duration with a high pitch. They are quickly muffled and usually are at the beginning/end of breathing.
When are the fine crackles found?
In cases of
- Bronchitis
- Lung oedema
- Pneumonia
- Lung fibrosis
Describe course crackles
They are usually lower-pitched with a longer duration than fine. You can hear them over the trachea/mouth with or without your steth
What do course crackles indicate?
fluid in the large airways
Describe Wheeze sounds of the lungs?
They have a longer duration with a relatively high frequency compared to crackles
What causes wheezes?
Sinusoidal (musical), narrowing of airway, caused by vibration of small bronchial walls.
Describe roncho lung sounds?
Longer duration but have deeper frequency than wheezes. Snoring sound.
What is the difference between stridor and stertor?
Stridor is a harsh, high-pitched sound produced by obstruction of upper airways, whereas stertor is a low-pitched nasopharyngeal obstruction.
What is a anacrotic pulse?
weak and delayed
What is a pulsus alternans?
Strong/Weak alternation
What is a pulsus paradoxus?
Weak arterial pulse during inspiration, strong during expiration
What is a pulsus bigeminus
Regular alteration of the pulse pressure caused by premature ventricular contraction
Describe how hepatojugular reflex occurs?
Right heart failure is an increase in RA pressure leading to an increase of hydrostatic pressure in the caval veins, resulting in backward failure. And pressure on the liver leads to a rise in venous pressure.
What does CRT evaluate?
Peripheral perfusion
What is a cough?
A sudden expiratory effort in which a loud expulsion of air occurs.
What is the name of a couch with blood in it?
Haemoptysis
What are the 4 causes of a cough?
- Respiratory: upper or lower airway and pulmonary disease
- Cardiac: severe LSHF or LA dilation with compression of left mainstem bronchus
- Pleural space disease
- Toxic
what is Eupnoea?
normal, unlaboured breathing.
What is dyspneoea?
respiratory difficult
What is Orthopnoea?
Severe respiratory difficult with inability to lay down.
What is Paradoxical breathing?
Breathing pattern in which the chest moves in on inhalation and out on exhalation.
What is syncope?
Defined as transient loss of consciousness (TLOC) due to cerebral hypoperfusion, characterized by a rapid onset, short duration, and spontaneous complete recovery.
(Congenital heart diseases in dogs and cats)
What are the 3 types of murmurs?
- Pathological
- Non-pathological – functional
- Non-pathological – Innocent
What are the most common CHD in dogs?
- Pulmonic Stenosis (30%)
- Patent Ductus Arteriosus (PDA, 17-25%)
- Subaortic Stenosis (15%)
What are the most common CHD in cats?
- Ventricular septal defect (VSD, 40-20%)
- PDA (3-10%)
- Tricuspid valve dysplasia (TVD, 5-10%)
- Atrioventricular septal defect (AVSD, ASD, 5-10%)
- Mitral valve dysplasia (MVD, 9-13%)
What breed of dogs has predispositions to Pulmonic and subaortic stenosis?
boxers
What breed of dogs has predispositions to PDA, persistent right aortic arch?
German shepards
What breed of dogs has predispositions to Pulmonic stenosis?
Bulldogs
What breed of dogs has predispositions to TVD?
labs
What breed of dogs has predispositions to MVD?
bull terrior
What is Pulmonic stenosis?
It is a structural malformation that obstructs the blood flow from the right ventricular outflow tract to the pulmonary artery.
What is the consequence of this obstruction of blood flow in pulmonic stenosis?
The heart tries to apply more pressure to push blood through, which results in concentric hypertrophy.
The narrowing of the right ventricular outflow tract can cause right ventricular concentric hypertrophy or decrease cardiac output.
In pulmonic stenosis what with RV concentric hypertophy or decreased cardiac output cause?
- RV concentric hypertrophy will lead to an increase in o2 concentration, causing more cardiac damage and resulting in arrhythmias, sudden death or RSHF.
- Decrease in cardiac output can cause LS volume depletion, forward failure or exercise intolerance.
What do you see on a radiograph of a dog with pulmonic stenosis?
- increased cardiac silhouette.
- Big RS heart, more than 2/3rds of the heart in front of the apex
- pulmonary artery is prominent and bulging
- increased sternal contact
On an ECG of dog with pulmonic stenosis what will you see?
- Right axis deviation
- Deep S waves in lead II, III with prolonged QRS duration: right bundle branch block (RBBB).
- Arrhythmias possible.
What will you see on an echocardiograph of a dog with pulmonic stenosis?
On the short axis, you will see the increased thickness of the RV and will see at the level of the pulmonic valve that it is operating sufficiently along with turbulence
How would you treat pulmonic stenosis?
Balloon dilation under GA, inflate balloon catheter causing more opening of the tract
What is PDA?
Patent Ductus Arteriosus is a part of fetal curculation and at birth it should close itself and regress to form the ligamentum arteriosus due to an increase in pressure. If it does not close it stays patent and allows blood shunting from L to R
T/F with a PDA it can go R to L too?
True
What are the consequences of a PDA?
PDA means that saturated blood that is meant to go back into systemic circulation goes back to the lungs.
This can increase flow to the lungs, resulting in more blood on the left side of the heart, which causes eccentric hypertrophy of the left side and ultimately CHF.
It can also cause an increase in the pulmonary artery, which causes pressure overload in the right side. The blood shunts from R to L, which is an issue as unoxygenated blood is going into systemic circulation.
What can unoxygenated blood going into systemic circulation cause?
cyanosis
When a dogs has PDA what are the clinical signs (L to R)
- Asymptomatic, loud continuous murmur on the left base (machinery murmur)
- Exercise intolerance, left sided congestive heart failure (CHF)
Bounding pulse (water hammer pulse)
What are the clinical signs of PDA when it is Right to Left?
- No continuous murmur (evtl. systolic on the right secondary to tricuspid regurgitation)
- Hindlimb weakness (differential cyanosis)
What dogs are predisposed to PDA
German Shepherd, Belgian Shepherd, Border Collie, and Australian Shepherd, as well as other large breeds such as the Newfoundland
On a radiograph of a dog with PDA what will you see?
- Enlarged heart
- RS is large
- Inverted D
- Knuckle with 3 bulges made up of the aortic arch, MPA and L Au
What is subaortic stenosis?
It is a malformation affecting the LV outflow tract, most commely via obstruction arising in the subvalvular level but valvular aortic stenosis is also possible
What are the consequences of subarortic stenosis?
obstruction causes narrowing of the LV outflow tract causing it to be underpressure which either results in LV concentric hypertrophy or lead to decrease in cardiac output.
What are the consequences of LV concentric hypertrophy or decreased cardiac output with subaortic stenosis?
- If LV concentric hypertrophy occurs it will lead to an increase in O2 concentration whihc will cause more cardiac damage, kead to arrythmias, sudden death or LSHF.
- If decreased cardiac output was to occur it will cause LS volume depeletion, forward failure, excerise intolerence or syncope.
What would the clinical findings be for a dog that has subaortic stenosis?
- Asymptomatic, ”just a murmur”
- Left cranial systolic crescendo-decrescendo murmur
- Weak pulse
Exercise intolerance, syncope, sudden death, left sided heart failure