USMLE

Description:	CV 4
Category:	USMLE
Created by:	Asclepius on 2008-10-19

Question	Answer
what does the P wave on EKG represent?	atrial depolarization
what does the PR segment on EKG represent? how long is it normally?	conduction delay through AV node - normally <200 msec
what does the QRS complex represent? how long is it normally?	ventricular depolarization (<120 msec)
what does the QT interval represent?	mechanical contraction of the ventricles
what does the T wave represent?	ventricular repolarization
why don't you see atrial repolarization on EKG?	it is masked by the QRS complex
what causes a U wave?	hypokalemia
delta wave on EKG is characteristc of what?	Wolff-Parkinson-White syndrome
in this syndrome, there is an accessory conduction pathway from atria to ventricle (bundle of Kent), bypassing the AV node	Wolff-Parkinson-White syndrome
this syndrome may result in reentry current leading to supraventricular tachycardia	Wolff-Parkinson-White syndrome
what is the hallmark of a transmural MI?	pathologic Q wave
increased capillary pressure is seen in what?	heart failure
decreased plasma colloid osmotic pressure is seen in what?	nephrotic syndrome, lver failure
increased capillary permeability is seen in what?	toxins, infections, burns
increased interstitial fluid colloid osmotic pressure is seen in what?	lymphatic blockage
three causes of early cyanosis	tetralogy of fallot, transposition of the great vessels, trucus arteriosis
three causes of late cyanosis	VSD, ASD, PDA
what is the most common congenital cardiac abnormality?	VSD
what causes Tetralogy of Fallot?	anterosuperior displacement of the infundibular septum
aortic stenosis proximal to insertion of ductus arteriosus?	preductal - infantile type
aortic stenosis distal to ductus arteriosus?	postductal - adult type
notching of ribs, hypertension in upper extremities, weak pulses in lower extremities?	coarctation of aorta
22q11 syndromes are asscociated with what cardiac defects?	truncus arteriosus, tetralogy of Fallot
what cardiac defects is Down syndrome associated with?	ASD, VSD
what cardiac defects is congenital rubella associated with?	septal defects, PDA
what cardiac defects are associated with offspring of diabetic mothers?	transposition of great vessels
Marfan's is associated with what congenital cardiac defect?	aortic insufficiency
lipid deposit in cornea	corneal arcus
what characterizes Monckeberg arteriosclerosis?	calcification of arteries, especially radial or unlar; usually benign (involves media - ring-like calcifications; 'pipestem')
arteriosclerosis in essential hypertension?	hyaline thickening of small arteries
arteriosclerosis in malignant hypertension?	hyperplastic 'onion skinning'
fibrous plaques and atheromas form in what part of arteries in atherosclerosis?	intima
risk factors for atherosclerosis?	smoking, hypertension, DM, hperlipidemia, family Hx
progression of atherosclerosis?	fatty streaks - proliferative plaque - complex atheromas
complications of atherosclerosis?	aneurysms, ischemia, infarcts, peripheral vascular resistance, thrombus, emboli
location of atherosclerosis?	abdominal aorta > coronary artery > popliteal artery > carotid artery
angina occurs with coronary artery disease narrowing greater than whta?	75%
retrosternal chest pain with exertion - what type of angina?	stable
angina that occurs at rest secondary to coronary artery spasm?	Prinzmetal's variant
thrombosis but no necrosis/worsening chest pain - what type of angina?	unstable/crescendo
where do red infarcts occur?	in loose tissues with collaterals, such as lungs, intestine, or following reperfusion
where do pale infarcts occur?	solid tissues with single blood supply - brain, heart, kidney, spleen
child with harsh systolic murmur, no diastolic murmur, and increased oxygen saturation in the RV?	VSD