Cardio Basics Flashcards
ECG and Echo
DfDx for pale mucous membranes
Anemia
Peripheral vasoconstriction
DfDx for bright red mucous membranes
Excitement
Peripheral vasodilation
Sepsis
Polycythemia
DfDx for blue/gray mucous membranes
Airway disease Pulmonary parenchymal disease Right to left cardiac shunt Hypoventilation Shock Methemoglobinemia
DfDx for icteric mucous membranes
Hemolysis
Hepatobiliary disease
DfDx for Jugular Pulsations
Jugular pulse DOES NOT indicate congestive heart failure
Indicate elevated right heart filling pressures or obstruction to filling of the right heart
Tricuspid insufficiency
Hypertrophied right ventricle (ex. pulmonic stenosis, pulmonary hypertension)
Certain arrhythmias (heart block)
DfDx of Jugular distension (+/- pulsations)
Occlusion of the cranial vena cava/RA by external compression (mass or thrombosis)
Very high right heart filling pressures (pericardial effusion)
Precordial thrill
Palpable Murmur
Loud murmur that has a palpable buzzing sensation on the chest wall over the heart
Shifted precordial impulse
Cardiac enlargement (right heart hypertrophy)
Mass lesions displacing the heart
Collapsed lung lobes allowing cardiac displacement
Focal accumulations of air or fluid
Decreased intensity of precordial impulse
Obesity Pleural effusion Pericardial effusion Weak cardiac contractions Thoracic masses Pneumothorax
What do you feel when feeling for a pulse?
Diastolic? Systolic?
Systolic!
Blood loss: will feel decreased pulse
Excitement; increase pulse
Causes of hyperkinetic pulses
High adrenergic tone
PDA (decreases diastolic)
Aortic regurgitation
Causes of hypokinetic pulses
Reduced stroke volume
Heart failure
Hypovolemia
Some arrhythmias
Causes of turbulent blood flow (general)
Murmur = turbulent blood flow (hear sound when there should be silence)
Increased velocity (narrowed vessels, abnormal valves, shunts)
Decreased viscosity (anemia, valves could be fine)
Large diameter vessels (horse, cows) - physiologic murmur
How do you describe murmurs
Timing (systolic or diastolic)
PMI
Pitch and quality
Intensity
Radiation
Murmur sounds are not correlated with disease severity
Most common dog murmur?
And what timing?
Mitral valve
Systolic (90%)
S1
What is it
Pathologic
Closing of the AV valves and vibrations of cardiac walls (deceleration of blood)
Pathologic:
Split S1 can be heard with ventricular premature contractions (VPCs)
S2
What is it
Pathologic
Closure of the pulmonic and aortic valves
Pathologic:
Split S2; delayed closure of the pulmonic valve (VPCs, RV hypertrophy) or aortic valve (VPCs, LV hypertrophy)
S3
What is it
Pathologic
Vibrations in the heart wall associated with rapid ventricular filling (normal in horses)
Diastolic sound
Pathologic:
Dogs and cats; dilated ventricles (DCM) and is referred to as a gallop rhythm
S4
What is it
Pathologic
Atrial contraction (normal in large animals)
Pathologic:
Dogs and cats; contraction of very dilated atria, secondary to ventricular hypertrophy (HCM) also called a gallop
When does Systolic occur (S phases)
Between S1 and S2
When does Diastolic occur (S phases)
After S2 and before S1
Timing of murmurs includes:
Systolic vs Diastolic
Continuous?
Early? Middle? Late?
PMI of murmurs includes
Localizing the lesion (PAM); basilar (top) or apical (bottom)
Identifying intercostal space
What side is a PDA heard on? A VSD?
PDA = left VSD = right
Common place for regurgitant murmur
Mitral (LAV)
Tricuspid (RAV)
Common place for an ejection murmur
Pulmonary stenosis
Subaortic stenosis
Physiologic
Continuous
PDA (left heart base)
Intensity/Grade (6)
1: very soft, localized to one region
2: soft, radiates to 2 heart regions
3: moderate, radiates to 3 heart regions (any mix)
4: loud, radiates all 4 heart regions
5: loud, radiates all regions, precordial thrill
6: hear when stethoscope is removed from chest wall
What does left sided congestive heart failure due to the lungs?
Pulmonary edema (effusion in cats)
End-inspiratory/initial expiratory fine crackles
Respiratory sounds:
Stertor and Stridor
Discontinuous sounds and wheezes heard without stethoscope
Respiratory sounds:
Crackles
Nonmusical, discontinuous sounds (crumpled paper)
Wheezes
Musical, continuous sounds
What does fluid in the lungs or pericardium indicate?
Congestive heart failure
Fluid accumulation in right vs. left sided heart failure
Right: ascites
Left: Pulmonary edema (fluid in parenchyma)
Lateral radiograph: normal heart
Should be less than 2/3 of chest cavity height.
Should be less than 3.5 IC spaces wide
DV radiograph: normal heart
Width: less than 2/3 of chest cavity in dog, less than 1/2 chest cavity in cat
Length: less than 5 IC spaces
Pulmonary vessels
Enlargement examples
Ventricular septal defect
PDA
Pulmonary venous hypertension
Occurs prior to left heart failure and man manifest as engorged pulmonary veins relative to arteries
Caudal vena cava enlargement
Systemic venous congestion
Elevations in right heart filling pressure
Compare size to aorta (should be 1:1 in size)
Pulmonary Patterns:
Bronchial
Increased opacity of airways
Doughnuts!
Examples:
Feline asthma
Canine Chronic Bronchitis
Pulmonary Patterns:
Interstitial
Cloudy/fuzzy parenchyma
Obscures edges of heart and vessels
Example: CHF Feline pulmonary edema Neoplasia Inflammatory fluid
Pulmonary Patterns:
Alveolar
Very progressed interstitial (flooded alveoli)
Bronchi are visible (air-bronchogram)
Parenchyma very dense to consolidated (soft tissue opacity)
Examples:
Pneuomonia
Pulmonary Patterns:
Vascular
Generalized enlarged pulmonary vessels (arteries and veins)
Examples:
PDA
VSD
Three classic radiographic findings of left heart failure
Left heart enlargement (especially left atrium)
Pulmonary venous enlargement
Interstitial opacity (especially around vessels); pulmonary edema
What are the 3 hallmarks of a reverse D? What does this indicate?
Right pressure overload
Right ventricle enlargement
Right atrial enlargement
Main pulmonary trunk bulge (enlarged right PA)
Also see:
Bronchointerstitial lung pattern (difficult to see vessels)
Small volume of pleural effusion
Radiographic findings in patient with Chronic Mitral Valve Regurgitation
LV enlargement
Left atrial bulge
Venous enlargement
Left auricular bulge
What occurs during the P wave?
Atrial muscle depolarization
What occurs during the PR wave?
Conduction from SA through AV node
What occurs during the QRS wave?
Ventricular muscle depolarization
What occurs during the T wave?
Ventricular muscle repolarization
Normal Lead II reading vs. abnormal (what is occuring?)
For dog and cat!
Normally: more heart mass on left so get a positive reading (QRS)
Abnormal: right ventricular enlargement indicating more muscle mass on right; get negative reading (QRS)
What information can you get from an ECG?
Heart rate
Heart rhythm and conduction
Chamber enlargement (not very sensitive) - duration can tell us this
Can NOT tell you about CHR or quality of cardiac muscle contraction
What does an ECG look like with pericardial effusion?
Low-voltage complexes
What does an ECG look like with hypothyroidism?
Low-voltage complexes
What does an ECG look like with hypoadrenocorticism?
Bradycardia
Spiked T wave
Flat P wave
Normal ECG heart rate:
Dogs? Cats?
Dogs: 70-160 bpm
Cats: 150-220 bpm
How do you determine HR from an ECG?
Count the QRS complexes in 3 seconds and multiply by 20
50 mm/sec paper: 30 boxes is 3 seconds
25 mm/sec paper: 15 boxes is 3 seconds
What is a sinus rhythm?
There is a normal P wave for every QRS
Normal heart rate
Normal similar shaped QRS
Regular, very little variation in P-P interval
Normal in dogs and cats
What is a sinus arrhythmia?
Irregular rhythm from SA node (normal in some species-dog-)
Pattern or increasing and decreasing heart rate because of a pronounced vagal tone (can be seen with respiration)
Gradual speeding and slowing of complexes
Varying P height; wandering pacemaker of vagal tone
ECG: what do you see with ventricular depolarization abnormalities?
T-wave large; get repolarization abnormalities
Can indicate RV enlargement
ECG: what does a large R wave indicate?
Left ventricular enlargement
DfDx for:
Tall P wave
Dogs: right atrial enlargement, sinus tachycardia
Cats: left or right atrial enlargement
DfDx for:
Wide P wave
Left atrial enlargement
DfDx for:
Absent P wave
Hyperkalemia
Atrial standstill
Atrial fibrillation
DfDx for:
PR/PQ shortening
High sympathetic tone
DfDx for:
PR/PQ Prolongation
First degree AV block
DfDx for:
Wide QRS
Ventricular enlargement
DfDx for:
Small QRS
Pericardial or pleural effusion
Pneumothorax
Hypothyroidism
Obesity
DfDx for:
QT prolongation
Hypo: kalemia, calcemia, thermia
Bradycardia
Conduction disturbance
DfDx for:
QT shortening
Hyperkalemia
Hypercalcemia
Digoxin
DfDx for:
Large T wave
Mycardial hypoxia
Bradycardia
Ventricular enlargement
Hyperkalemia
DfDx for:
Small T wave
Normal for cats
Pericardial or pleural effusion
Pneumothorax
Hypothyroidism
Obesity
Ectopic Complexes:
Supraventricular
Above the ventricles (within the atria)
P-wave can be absent
Premature beat; impinging on T wave
Ectopic Complexes:
Ventricular
Below the AV node
Wide and bizzare beat (QRS does not look right)
What is an escape beat?
Occurs after a long pause; helping keep the patient alive!
Severe bradycardia
Heart block
Bradyarrhythmia
Common causes
Not always pathologic (especially in species with strong autonomic tone)
Sinus node issue:
Decreased rate of P waves or absent P waves
AV node issue:
Slow/absent conduction through the AV node
P waves without QRS
Sinus bradycardia/bradyarrhythmia
Regular but a low rate
Normal P wave for every QRS BUT P and QRS are occuring at a slow rate
Normal PR and QRS
Sinus bradycardia
Treatment
Address underlying cause!
High vagal tone
Anesthesia/sedation (may need to give atropine)
Medications
Identify and address the underlying cause
Sick Sinus Syndrome
Sinus node NOT normal
Abnormal rhythm disturbance in older small breed dogs
Involves:
Sinus bradycardia
Sinus arrest (pause without P or QRS) -> may then see a ventricular escape rhythm
Atrioventricular (AV) block - due to SA pause
Supraventricular tachycardia
Animal may have collapsed (sinus arrest)
AV node disease
Normal or elevated P wave rate
Decreased rate of conduction from P to QRS (long PR interval)
Can get complete block of AV node = AV Block
AV Node Disease (3 types)
First degree
Second degree
Third degree
First degree AV Block
Usually due to vagal tone
Physiologic process most often
Long space between P and QRS (prolonged PR)
Can have a normal HR
Second degree AV Block
Differentiation?
Intermittant P without QRS
Normal to slow HR (usually irregular)
Can be normal in horses
Seen in dogs with high vagal tone or AV node disease
Differentiate with atropine; block will resolve if vagally mediated
Third degree (complete) AV Block
P and QRS are regular but not related (doing their own thangs)
Slow regular HR
Ventricular QRS activity is from escape foci in AV node or ventricle (wide/bizarre)
AV node fails and then other pacemakers in ventricles kick in to keep patient alive (keeping CO)
Third degree (complete) AV Block
Symptoms
Treatment
Symptoms:
Weakness
Exercise intolerance
Collapse
Requires pacemaker (ventricular beats are not using normal His purkinjie system) Not generally responsive to medical treatment
Three types of Tachycardia
Sinus
Supraventricular
Ventricular
Sinus Tachycardia
Information
Causes
Treatment
QRS shape: Normal
Regularity: Regular
Onset: Gradual
P wave: Normal
Increased HR that originates in sinus node
Causes: pain, excitement, hypotension
Treatment:
Address primary cause
Supraventricular Tachycardia
Information
3 or more supraventricular beats in a row
QRS: Normal
Irregular
Onset: Abrupt (ends abruptly too)
P wave: Abnormal
Ventricular Tachycardia QRS Regularity Onset P wave
QRS: Wide/bizarre
Regular (occurs often)
Onset: Abrupt
P wave: Not associated
Supraventricular tachycardia
Causes
Atrial enlargement Enlarged hilar lymphnodes Thoracic masses Pulmonary inflammation Electrolyte disturbances
“Painful” to atrium
Atrial Fibrillation
What is it?
Type of supraventricular tachycardia Rapid heart rate Irregularly irregular R-R intervals (no pattern) Continuous No obvious P waves \+/- f waves
Atrial Fibrillation
Causes
Small animal:
Severe atrial enlargement
Dilated cardiomyopathy
Chronic valvular disease
Uncommon in cats (but could be seen in HCM)
Treatment of Atrial Fibrillation and Supraventricular tachycardia
Goal: decrease HR through decreasing conduction through AV node
Will not get a return to normal rhythm all the time
Rx: Calcium Channel Blocker (Diltiazem) Digoxin Beta Blocker (Atenolol, sotalol) Combinations (Digoxin and Diltiazem)
Equine Atrial Fibrillation
No noticeable P waves
Irregularly irregular
Lone atrial fibrillations can be normal (have large atrial mass that it can happen sometimes)
Equine (lone) Atrial Fibrillation
Lone; no evidence of structural heart disease and successful treatment -> converts rhythm to normal sinus rhythm
Horses should be treated; will decrease their performance
Rx: Quinidine (Digoxin possibly)
Want to treat ASAP in hopes to return to a normal rhythm
Relapse is common
Ventricular Tachycardia
3 or more ventricular premature beats (VPC) in a row
Ventricular Tachycardia
Treatment
Acute
Chronic
Sudden death can result from VTach
Antiarrhythmics decrease risk of VTach but sudden death avoidance is not gauranteed
Acute/Emergency:
Lidocaine (IV bolus); after response can switch to CRI
Chronic:
Mexilitine
Sotalol (beta-blocker)
Atenolol (beta blocker)
Indications to treat VTach
Sustained VTach: > 140-160 bpm
>20 VPCs per minute
Multiform VPCs
Arrhythmias with myocardial failure present
Breeds at risk for sudden death (Dobermans, Boxers)
Hypotension
VPCs close to the T wave of the proceeding complex
Critically ill patients
Ventricular Fibrillation
Disorganized electrical activity, end result of VTach
NO CO: no pulse generated
Sudden death (asystole)
Ventricular Fibrillation
Treatment
Electrical defibrillation
Antiarrhythmics not effective
Echocardiogram
Two dimensional use
Anatomic evaluation of the heart
Information on anomalies, chamber enlargements, pericardial effusion
Echocardiogram
M-Mode
Evaluates cardiac motion over time in a single “ice pick” beam
Resolution of chamber surfaces is more readily defined for accurate measures (hypertrophy? thinning?)
Diastole: max volume
Systole: min volume
M-Mode
MV View
Evaluates mitral valve motion
Evaluates left ventricular diastolic function
M-Mode
LA:Ao View
Evaluates aortic valve motion
Evaluates left atrial size
LA: Ao should be a 1:1 (if increased usually due to atrial enlargement)
Aortic valve looks like boxes
Fractional Shortening (FS%)
Difference between diastole and systole size (M-Mode)
Normal
Dog: 25-40%
Cats: 35-50%
What does color doppler echocardiography evaluate?
Turbulence and direction of flow (qualitative)
Blue
Away
Red
Towards
Green/Yellow = turbulence and high velocity
Should have no color in atrial chambers during systole!
What does spectral doppler echocardiography evaluate?
Flow speed/velocity (quantitative)
Can identify pressure gradient across stenotic valve or shunt (cardiac chamber pressures)
What are the normal chamber pressures?
RA: 2-8 RV: 15-30/2-8 PA: 15-30/4-12 LA: 2-10 LV: 100-140/3-12 Aorta: 100-140/60-90
If any are significantly higher there could be a potential stenosis
