3/31 - UWorld Flashcards
What is an Aschoff body and what disease is it associated with?
A granuloma within the myocardium consisting of macrophages with slender chromatin ribbons (Anitschkow cells)
Caused by acute rheumatic fever
In what situation will you hear a continuous murmur and palpable thrill over the L upper sternal border?
Patent ductus arteriosus
What causes increased myocardial cell size in transient myocardial ischemia and why?
Intracellular Ca2+ accumulation
Ischemia leads to anaerobic metabolism which cannot maintain ATP levels
Decreased ATP means that Na+/K+ ATPase cannot work –> increased intracellular Na+ and decreased K+ –> intracellular Na+ will cause increased action of Na+/Ca2+ exchanger, causing increased intracellular Ca2+
What is Wolff-Parkinson-White (WPW) syndrome and how does it present on EKG
An abnormally fast accessory conduction pathway from atria to ventricle (Bundle of Kent) bypasses the rate-slowing AV node –> ventricles begin to partially depolarize earlier (“pre-excitation”) –> characteristic delta wave with widened QRS and shortened PR
Delta wave on EKG
Describe the pathogenesis of an atherosclerotic plaque
Endothelial cell injury (e.g. lipids) results in increased endothelial permeability, enhanced leukocyte adhesion, and altered gene expression
Endothelial dysfunction also promotes platelet adhesion, aggregation, and release of growth factors and cytokines
PDGF released promotes migration of smooth muscle cells from the medial to the intima and increased smooth muscle cell proliferation
Platelets also release TGF-B, which induces collagen production
List arteries most affected by atherosclerosis in order
(1) Abd aorta
(2) Coronary arteries
(3) Popliteal a.
(4) Internal carotid
(5) Circle of Willis
What is the cause of a 4th heart sound
Occurs during atrial systole (atrium contracting against a stiff ventricle)
What is the cause of S3?
Rapid flow of blood from the atria to the ventricles during diastole
Indicates volume overload (e.g. CHF, mitral or tricuspid regurg)
What is myocardial hibernation
Due to state of chronic myocardial ischemia in with myocardial funciton and metabolism are reduced in order to match the reduction in blood flow
This is done in order to prevent myocardial necrosis
Leads ot decreased contractility and LV function
Coronary revascularization and restoration of blood flow to hibernating myocardium improves contractility and LV function
What is the effect of ANP in response to volume expansion
Increased GFR via afferent dilation and efferent contriction
This leads to increased natiuresis and diuresis
