congenital heart disease Flashcards by Jessica Ernst

patent ductus arteriosus cause

lack of inhibition of local prostaglandins

normally prostaglandins would cause an increase in smooth muscle proliferation and contraction leading to closure of the duct

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pathophysiology of PDA

continuous murmur

increased pulmonary flow and increased venous return via the pulmonic veins to the left side of the heart

volume overload on left side causes atrial and ventricular eccentric hypertrophy & increases left ventricular diastolic pressure

pulmonary edema

hyperkinetic pulse

dilation of proximal aorta and main pulmonary artery

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right to left shunting PDA

extremely rare

in dogs <6 months old

pressures in pulmonary artery and aorta tend to be similar

pulses not hyperkinetic

concurrent pulmonary hypertension

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what breeds are most commonly affected with PDA?

chihuahuas, collies, Maltese, other poodles, toy pomeraninans, shelties

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are males or females more likely to have PDA?

females 2x

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clinical findings of PDA

left sided congestive heart failure signs (tachypnea, coughing, etc)

arterial pulses-hyperkinetic

continuous thrill at left CD heart base

continuous murmur

point of maximal intensity of PDA-far cranial and high over left heart base

soft systolic mumur over mitral valve (secondary to increase in left ventricular size)

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ECG findings in PDA

may be normal

change consistent with left atrial and left ventricular enlargement (P wave prolonged)

R wave amplitude increased

+/- atrial and ventricular tachyarrhythmias in advanced cases (atrial fibrillation)

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thoracic radiograph findings of PDA

pulmonary overcirculation

dilation of main pulmonary artery and proximal aorta

left atrial and ventricular enlargement

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ECHO findings of PDA

perform to confirm dx and exclude other concurrent congenital heart defects

left atrial and ventricular dilation

spectral/color flow Doppler: abnormal retrograde flow via ductus into pulmonary artery

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natural history of PDA

64% will die within 1 year-remaining are likely to develop complications, some live full lives

px with correction for uncomplicated PDA cases: confers an outstanding long term px, considered to be curative

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treatment of PDA

ductal closure via surgical ligation or placement of transcatheter ductal occluder

perform ASAP

stabilize patients before sx

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subaortic stenosis

common and important congenital malformation of K9 heart

Newfoundlands!

develops progressively

usually subvalvular stenosis

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what happens following PDA occlusion?

the heart returns to normal

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clinical signs of Right to left PDA

hypoxemia

differential cyanosis

hind limb weakness

polycythemia

auscultation: no murmur, split S2 sound

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therapy for right to left PDA

don’t occlude

phlebomtomy-maintain PCV below 65% to prevent hypervisocity of blood

sildenafil, propranolol

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how does sildenafil work?

phosphodiesterase 5 inhibitor: increased cGMP and NO signaling

vasodilation of pulmonary arteries-reduction of pulmonary hypertension, decreased right to left shunt

how does propranolol work?

non-selective beta-blocker

prevent exercised induced systemic vasodilation

what is the first line of therapy for pulmonary hypertension?

sildenafil

pathophysiology of pulmonic stenosis

primary malformation of pulmonic valve

causes right ventricular outflow tract obstructions from the muscular ridges and fibrous membranes

arterial obstructions

concentric hypertrophy

signalment of pulmonic stenosis

dogs: english bulldog, scottish terrier, fox terrier, mini schnauzer, chihuahua

feline-rare

clinical signs of pulmonic stenosis

most are asymptomatic during first year

syncope

exercise intolerance

cyanosis

abdominal distension

sudden death

PE finding of pulmonic stenosis

left sided ejection (systolic) basilar murmur over pulmonic valve

prominent jugular pulse

prominent apex beat on right hemithorax

murmur of tricupsid regurgitation

ECG finding of pulmonic stenosis

right ventricular enlargement

shift in MEA to right side

QRS complex negative

Tall p waves due to right atrial enlargement

thoracic radiographs of pulmonic stenosis

right ventricular enlargement

prominent post-stenotic dilatation of main pulmonary artery

Echo findings of pulmonic stenosis

confirm dx of pulmonic stenosis and evaluate severity of defect concentric right ventricular hypertrophy with prominent papillary muscles and flattening/displacement of setpum towards the left post stenotic dilation of pulmonary artery doppler: Benoulli equation (change in P=4V²) mild \<50 mg, moderate (50 to 100), severe \>100

px of pulmonic stenosis

mild, moderate cases-can live a normal life moderate to severe: exercise intolerance, extertional syncope, cardiac arrhythmias, secondary tricupsid regurgitation with right sided congestive heart failure and/or atrial fibrillation, sudden death

therapy of pulmonic stenosis

balloon valvuloplasty: usually won't re-restrict

english bulldogs and pulmonic stenosis

no Left coronary arteries, a branch from right coronary artery runs over pulmonic artery leading to pulmonic stenosis dont try balloon valvulopasty

medical management of pulmonic stenosis

fish oil with omega 3 fatty aicds beta blockers: atenolol or propanolol patients with right sided CHF: diuretics, ACE inhibitors, abdominocentesis, positive inotropic drugs are CI (ie digoxin, pimendoben)

subaortic stenosis

progressive subvalvular stenotic ring consists of loosely arranged reticular fibers, mucopolysaccharide ground substance, and elastic fibers coronary circulation can be abnormal focal areas of myocardial infarction and fibrosis

pathophysiology of subaortic stenosis

left ventricular outflow obstruction left ventricular systolic pressure increases and systolic pressure gradient across outflow tract concentric hypertrophyof LV late and slow rising arterial pulse systolic murmur and post stenotic dilatation of ascending aorta and aortic arch left atrial concentric hypertrophy severe: left sided heart failure

signalment of subaortic stenosis

newfoundland, boxer, german shepherd and golden retriever, rottweilers, german short-haired pointers

clinical findings of subaortic stenosis

asymptomatic soft to moderately intense systolic murmur over aortic valve sudden death severe: exertional tiring, syncope or left side congestive heart failure

PE of pulmonic stenosis

left systolic murmur: radiates to right cranial thorax, radiate through carotids to and fro murmur-systolic and diastolic arrhythmias weak femoral pulses: late peak

ECG of pulmonic stenosis

normal left ventricular enlargement significant S-T segment depression-indicator of myocardial ischemia and fibrosis any ventricular arrhythmias should be considered important