Cardiology USMLE step 1 Quiz with complete solutions | Latest 2023/2024

Cardiology USMLE step 1 Quiz with complete solutions | Latest 2023/2024 truncus arteriosus forms -- forms the ascending aorta and pulmonary trunk blunt chest trauma + hypotension, tachycardia + Jugular venous distension -- Acute cardiac tamponade...... right atrial and ventricular collapse on echocardiogram Holosystolic murmur + murmur increase with inspiration (carvallo sign) -- Tricuspid regurgitation Cardiac output determined by Swan Ganz catheter by applying the fick principle -- Cardiac output = rate of 02 comsumption / arteriovenous 02 content difference during excercise there is increase or decrease c02 production co0 content of venous blood arterial c0 and 02 conent cardiac output SVR -- 1. vasodilation in skeletal muscle and vasoconstriction in the splanchnic circulation 2. decrease SVR and increase HR = increase Co 3. increase 02 extraction by tissues =increase c02 production increase c02 content of venous blood arterial c02 and 02 remains normal bc respiratory compensation Aortic regurgitation Aortic pressure and Left ventricular pressure -- Aortic regurgitation = rapid loss of aortic pressure during diastole due to blackflow of blood into the left ventricle Aortic pressure 160/60 Left ventricular pressure 160/10 normal 120/80 and 120/10 Hemodynamic measurements in shock hypovolemic CVP= right side preload PCWP = left side preload Cardiax index= LV output SVR = afterload Sv02 -- CVP= right side preload --- decrease PCWP = left side preload --- decrease Cardiax index= LV output --- decrease SVR = afterload --- increase Sv02 --- decrease Hemodynamic measurements in shock Cardiogenic shok CVP= right side preload PCWP = left side preload Cardiax index= LV output SVR = afterload Sv02 -- CVP increase PCWP increase LV output decrease SVR increase Sv02 decrrease coronary perfusion pressure decrease Hemodynamic measurements in shock Obstrutive CVP= right side preload PCWP = left side preload Cardiax index= LV output SVR = afterload Sv02 -- CVP increase Decrease but pn tamponade PCWP increase paradoxically due to external compresion b pericardial fluid LV output decrease Sv02 - decrease Hemodynamic measurements in shock Distributive CVP= right side preload PCWP = left side preload Cardiax index= LV output SVR = afterload Sv02 -- CVP decrease PCWP decrease LV increase SVR decrease Sv02 increase on neurogenic shock, due to impaired sympathetic reflex .. LV and SV02 are usually decrease right side artery is decreased by a factor of 16 compared to the left what percentage has the radius of the lumen been reduced? -- 50% reduced... bc P1-P2 * r'4 ------ nL noted: radius of the blood vessel raised to the 4th power Aortic stenosis Aortic pressure and Left ventricular pressure -- Aortic pressure 110/75 Left ventricular pressure 160/20 normal 120/80 and 120/10 Verapamil to treat Paroxysmal supraventricular tachycardia mechanism of action -- Blocking L type Ca channels, in cardiac slow response tissues, cause SLOW of PHASE 4 of depolarization Bulbus cordis forms -- forms outflow tracts (smooth parts of R and L ventricles) -conus cordis is the smooth part that directly feeds into truncus arteriosus endocardial cushion -- forms atrial septum, membranous part of IV septum, and AV/semilunar valves what disease is the endocardial cushion specifically important in? -- down syndrome primitive atrium -- forms trabeculated (columnar) part of R and L atria