Syncope and Murmur Dogs Flashcards by jared Jensen

syncope (or cataplexy)

sudden loss of consciousness and postural tone

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sudden loss of consciousness and postural tone

syncope (or cataplexy)

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what other signs may occur with syncope

-paddling
-loss of bowel/urination
-seizures

these signs are no discriminatory

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Pulse deficits may be observed on examination in what arrhythmias

Any arrhythmia with an early beat where the heart contracts before having effective time to fill

1) Premature atrial complexes
2) Premature ventricular complexes
3) Atrial fibrillation
4) Ventricular tachycardia

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What is a pulse deficit

when you hear an asucultated beat but you dont appreciate a pulse

usually due to left ventricle contracts but fails to generate enough strength to generate a pulse or fails to open up the aortic valve

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occur when an abnormal heart rhythm causes the heart to contract prematurely and close the AV valves (causing a heart sound) but the stroke volume of the early beat may be inadequate to open the aortic valve or to lead to a palpable pulse in a peripheral artery

Pulse deficits

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What are your differentials for a fainting event **

1) Seizure
-Epilepsy
-Metabolic: hypoglycemia, hypocalcemia, uremia, HE
-Infectious: Viral, Protozoal, Fungal, Bacterial
-Immune-mediated
-Traumatic
-Neoplastic
-Toxic

2) Syncope
-Cardiac: Tachyarrythmia, Bradyarrhythmia, Low CO
-Neurogenic: Reflex-mediated or situational
-Exertional syncope
-Cyanotic heart disease
-Drug related
-Hyperviscosity

2) Syncope

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How might you differentiate seizure from syncope *

seizure: post-ictal period

syncope: acute loss of consciousness and postural tone but then goes back to normal in seconds to minutes

*neuro and cardiac exams

breeds predilections

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What are causes of syncope

Cardiac
1) Tachyarrythmia
2) Bradyarrhythmia
3) Low CO
others

4) Neurogenic: Reflex-mediated or situational
5) Exertional syncope
6) Cyanotic heart disease
7) Drug related
8) Hyperviscosity

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T/F: sinus bradycardia can cause syncope

True- but it does not cause a pulse deficit

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What arrhythmias might cause syncope

1) PVCs
2) PACs
3) Pronounced Sinus Arrhthmia
4) 2nd degree heart block
5) Atrial fibrillation
6) Atrial flutter (with variable conduction)
7) Atrial tachycardia (with variable conduction)
8) Paroxysmal Ventricular tachycardia

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What causes a left basilar systolic heart murmur

1) Aortic Stenosis
-Subvalvular
-Valvular
-Mass obstruction

2) Pulmonary valve stenosis: congenital or secondary to increased flow (ASD)

Functional: elevated outflow velocity (athletic heart) , anemia, thyrotoxicosis, pyrexia

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murmurs unrelated to structural heart disease
can be secondary to athleticism, excitement
common in the Boxer and other athletic breeds

may reflect a relatively smaller aorta

functional heart murmurs

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what breeds might have a functional heart murmur

Boxer and other athletic breeds

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What might cause a functional heart murmur

secondary to athleticism and excitement
-elevated outflow velocity, anemia, thyrotoxicosis, pyrexia

(not a structural heart disease)

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What should you do for diagnostics for a dog with syncope **

1) Blood pressure
2) Electrocardiogram *** (preferred)
3) Echocardiogram
4) Bloodwork - CBC & Chemistry (+/- cardiac troponin)
5) Splenic ultrasound
6) +/- Holter or Event Monitor
7) +/- Thoracic radiographs

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What is a normal systolic blood pressure in a dog

110-160 mmHg

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T/F: PVCs have a QRS that is wider

true- and it is much different in appearance than sinus complexes

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What are the different patterns of premature ventricular complexes that you can have

1) Single
2) Couplet
3) Triplet
4) Bigeminy
5) trigeminy

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What is ventricular bigeminy

VPCs that alternate with normal sinus complexes

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What is ventricular trigeminy

VPCS that occur after two normal sinus complexes

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How can you tell which ventricles the PVCs are originating from *

Right ventricle: depolarization along lead II will have a positive R

Left ventricle: depolarization direction opposite lead II; negative S

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PVC that is postive on lead II originate from the

right ventricle

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PVC that is negative on lead II originate from the

left ventricle

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What are the differential diagnoses for PVCs **

HEAD H- heart disease: cardiomyopathy, myocarditis, etc E- Endocrine / Metabolic: thyroid excess, hypokalemia A- Autonomic imbalance: elevated sympathetic tone D- Drugs/toxins: digoxin, cocaine, etc S- Systemic issues: splenic disease, GDV, sepsis, DIC, etc

What autonomic imbalance can lead to PVCs

elevated sympathetic tone

What drugs/toxins can lead to PVCs

Digoxin Cocaine Chocolates

What systemic issues can lead to PVCs

Splenic disease GDV sepsis DIC

unrecogonized splenic masses can cause

ventricular ectopy

worn for 24 to 48 hours in hime environment allows for objective assessment of treatment efficacy

Holter Monitor -ambulatory ECG

How many ventricular ectopic beats are normal in 24 hours?

<50 is normal

What heart conditions do Boxers and Bull dogs typically get

Arrhythmogenic right ventricular cardiomyopathy

what is the pathophysiology of Arrhythmogenic right ventricular cardiomyopathy *

1) Fibrofatty replacement of ventricular myocytes 2) Allows for anatomic substrate for ventricular ectopy typically in right ventricle, may progress to the left and cause CHF

What breeds commonly get Arrhythmogenic right ventricular cardiomyopathy

Boxers and Bulldogs

What is your preferred emergency therapy for ventricular tachycardia

Iv lidocaine

What do you do therapeutically for ARVC **

1) Intravenous antiarrhthmics: IV lidocaine*, procainamide, amiodarone 2) Oral antiarrhthmics (at home): Sotalol*, Amiodarone, Mexiletine

Describe the EKG features of ventricular tachycardia

premature wide and normal quick

All of the following may cause a hyperkinetic pulse except -Aortic stenosis -Aortic regurgitation -PDA -Anemia -Arteriovenous fistula -Bradycardia

What factors influence the intensity of the pulse we feel

1) Pulse pressure (difference between systole and diastole) 2) Vascular tone (old patients with stiff vessels might have intense pulse) 3) Cardiac output 4) Volume of the blood 5) Run off of blood from aorta drops diastolic pressure (Aortic regurgitation, PDA, Arteriovenous fistula)

T/F: bradycardia is associated with a stronger/bounding pulse

True

T/F: anemia is associated with a stronger/bounding pulse

True - increased plasma volume creating more bounding ulse

How does aortic stenosis

narrowing of the outflow, takes longer so the rate of pulse pressure rise is longer

What might cause a truly continuous heart murmur

PDA AV fistula Rare defects (AP window)

What might cause a gallop sound?

1) S4 (atrial filling) -Stiff ventricle -Hypertension -HCM 2) S3 (ventricular filling) -Volume distended LV -CHF gallop

an extra sound within the heart beat during diastole

Gallop can be S4 (atrial filling) or ventricular filling

What might cause you to hear a S4 sound

S4 (atrial filling) -Stiff ventricle -Hypertension -HCM

What might cause you to hear a S3 sound

S3 (ventricular filling) -Volume distended LV -CHF gallop

closure of the mitral / tricuspid sounds

closure of the semilunar valves

a gallop sound that occurs later in diastole

S4- dub lub dub

a gallop sound that occurs right after S2

S3 -lub dub dub

What might sound like a continuous murmur

Combined systolic and diastolic murmurs 1) VSD and Ao regurgitation 2) Ao stenosis and Ao regurgitation 3) PS and pulmonary regurgitation

What are the top 5 loud systolic murmurs heard in puppies ***

1) Subaortic stenosis 2) Pulmonary valve stenosis 3) Ventircular septal defect 4) Tricuspid valve dysplasia - regurgitation 5) Mitral valve dysplasia- regurgitation

Subaortic stenosis causes what kind of murmur

systolic murmur, heard best over the left heart base, poor femoral pulse

What kind of murmur is heart with pulmonary valve stenosis

systolic murmur, head best over left heart base

T/F: dogs with pulmonary valve stenosis have an abnormal pulse

False

T/F: dogs with subaortic stenosis have an abnormal pulse

True

VSD causes ________ murmurs best heard over the __________

systolic murmurs best heard over the right thorax

Tricuspid valve dysplasia with regurgitation causes a _________ murmur heard best over the ________

systolic murmur heard best over the right apex

Mitral valve dysplasia with regurgitation causes a _________ murmur heard best over the ________

systolic murmur heard best over the left apex

What should you do diagnostically for a puppy with a continuous murmur

Thoracic Rads Echocardiogram Blood Pressure +/- blood work

What is the best diagnostic test to confirm CHF

thoracic rads

T/F: puppies tend to have little lower blood pressures at younger ages

true: ex 95mmHg might be normal

A 6mo puppy patient presents with respiratory distress. Upon thoracic rads you see LV enlargement, Ao dilation, pulmonary overcirculation, and perihilar edema with an interstitial lung pattern. What medication do you give

Furosemide

9week old puppy has -severe LA and LV dilation -hyperdynamic LV function -continuous, high velocity flow entering MPA -Mild mitral regurgitation -elevated aortic velocity what is the diagnosis

PDA

How does PDA lead to mitral regurgitation

blood leaves aorta and goes back through to the left atrium and pulls the mitral leafs appart causing regurgitation

Why might a patient with PDA have elevated aortic velocity

Increased venous return to the left heart

In fetal circulation ______ blood goes to pulmonary arteries and then across the ______ to the _____ to end up in the placenta

deoxygenated blood to PA and then across ductus to Ao and back to placenta

in fetal circulation, where does oxygenation occur

placenta, then returns through umbilical vein, across atrial septum to the left heart and body

ductus arteriosus normally closes by

1 week of life and becomes the ligamentum arteriosus

What allows closure of the ductus arteriosus

smooth muscle allows active closure after birth persistency is a defect in this muscle the absent muscle limits constriction and closure

Why do you hear a continuous murmur with a PDA

Left to right shunt

What are the 7 sequelae to a PDA *

1) Aortic dilation (ductal bump) 2) Pulmonary overcirculation 3) Increased venous return 4) LA dilation 5) LV eccentric hypertrophy / dilation 6) Continuous murmur from L-R shunt 7) Hyperkinetic shunt

What are the physical findings of PDA

1) Loud, continuous machinery murmur, flow during systole and diastole. Ao pressure is always higher than PA pressure 2) May be left apical murmur of Mitral regurgitation as well 3) Pulmonary crackles if CHF in severe cases 4) Rhythm abnormalities can occur due to cardiac enlargement (atrial arrythmias) 5) Pulse quality is very strong, bounding

What is the pulse of a patient with a PDA

very strong and bounding -Wide pulse pressures (systolic - diastolic) ex: 132/52 -secondary to diastolic run-off into PA = lower diastolic leads to pulse being bounding, water hammer, hyperkinetic

What happens to the pulse once the PDA is ligated

the diastolic pressure will increase

How is PDA treated in dogs

Close via interventional occlusion (catherization) or by open surgical ligation *treat as early as possible medical management if symptomatic: diuretics, ACE-inhibitors, pimobendan (if in CHF)

Uncorrected PDA may lead to

high probability of premature death

small PDA results

normal lifespan if closed

What are the results of a large PDA

progressive myocardial failure from volume overload leading to CHF

What arrythmia can occur with PDA

atrial fibrillation from LA enlargement

If a patient with a PDA is symptomatic, what medical management should you do

Diuretics ACE-inhibitors Pimobendan (if in CHF)

Where is the approach to PDA surgical ligation

L 4th intercostal retract lungs double ligature

What is the risk of surgical PDA ligation

Ductal tear Hemorrhage

What is the most common congenital heart defect in the dog

PDA or Pulmonary Stenosis

Where is a PDA heart murmur heard loudest

continuous (machinery) murmur; heard loudest at the left heart base (craniodorsal)

T/F: if closed PDA carries an excellent prognosis

True if untreated, they progress to L CHF, and high mortality in year one

Intervention for PDA is either

Surgical or transcatheter to ligate/occlude the ductus catherization depends on the size of the femoral artery. if you can get a large enough catheter in it then it can be done with catheters

What are the features of an innocent / functional heart murmur

1) No structural changes 2) Soft (grade 1 or 2/6) 3) Systolic

What is the most common form of congenital heart disease in the cat

VSD