Flashcards in Cardiomyopathy and anti-arrythmatic Deck (64)
What si restrictive cardiomyopathy histology?
patchy or diffuse intersitial fibrosis and disease specific changes
What is the clinical features of RCM?
congestive heart failure
--severe pulmonary congestion
similar S/S as constricitve pericarditis
Dx: endomyocardial biopsy
What happens in senile cardiac amyloidosis?
transthyretin (prealbumin)-deposits in ventricles and atria
>60 yrs of age
What are the restrictive hemodynamics?
pressure atrophy of fibers
deposition in regions of conduction system leads to arrhythmiass
endomyocardial fibrosis, large mural thrombi, peripheral eosinophilia, eosinophilic infiltrates in organs
Endocardial fibroelastosis is indicated by what?
common first two years of life, in young children in africa, focal or diffuse fibroelatic thickening
What can hyperthyroidism cause with respect to the heart?
tachy, palpitations and cardiomegaly
What can hypothyroidism cause with respect to the heart?
CO is decreased
flabby, enlarged and dilated
What is the effect of catecholamines on the heart when induced either in intesnse stress or froma pheochromocytoma?
What is afterdepolarizations?
spontaneous action potentials during or immediately after phase 3 repolarization. Produced by abnormal Ca2+ influx during or after phase 3 of ventricular action potential
leading to premature contractions and ventricular tachycardia
observeed with digoxin toxicity and conditions that prolong QT interval
Quinidine therapy results in what?
action potential prolognation increased QT duration, early afterdepolarizations and torsade de pointes
Class 1 are sodium channel blockers do what?
bind fast sodium channels in the open and inactivated states and dissociate from channels during resting state
What is in ddrug class 1a?
quinidine, procainamide, disopyramide
What is the drug dissociationrate of drug class 1a?
What is the drug dissociation of drug class 1B?
lidocaine, mexilitene; rapid
What is drug dissociation rate of class 1C?
What is drug class 1a mechanism of action?
slow phase 0, and conduction velocity and prolong action portential duration and refactory period
Class 1b drugs does what?
greater affinity for inactivated vs open channel
What is special about lidocaine?
extensive first pass hepatic inactivation; more active in ischemic tissue due to less negative resting membrane, minimal effect on normal cardiac tissue
What is class 1c drugs?
block fast sodium chanels more potently than class 1 agents, slow conduction throughout heart, less effect on K+ current
What is flecainide used to treat
SVT and VT,
may inhibit Ca2+ releases from cardiac SR
What is propafenone side effects?
ventricular proarrhythmia, agranulocytosis, anemia, thrombocytopenia
What are class II Beta-blockers do?
inhibit sympathetic activation of cardiac autmoaticity and conduction
effect mainly occurs at AV node refactory period;
What are class III anti-arrhythmic drugs?
block potassium recitifier, demonstrate reverse-use dependence
with more potent Kv block occuring at slower heart rates.
What is amiodarone?
iodinated compound, half life approx 40 days
decrease SA node automaticity, decrease AV conduction velocity
What are the side effects of amiodarone?
hypothyroidism, hyperthyroidism, neulogic toxicity, and more
What does amiodarone block?
Ikr and Iks
What does sotalol do?
selectively blocks beta-adrenoreceptors and delayed recitifier potassium channel
slow AV conduction velocity
What does dofetilide do?
block rapidly activating delayed recitifier channel,may prolong QT and produce TdP; blocks Ikr