Cardiac PCCN Test Questions and Answers(A+ Solution guide)

Coronary artery perfusion is dependent upon: A. Diastolic pressure B. Systolic pressure C. Afterload D. SVR - Answer A. Diastolic pressure Rationale: Diastolic pressure in the aortic root is higher than left ventricular end diastolic pressure (LVEDP) (the pressure exerted on the ventricular muscle at the end of diastole when the ventricle is full). This enables blood to flow from a higher pressure through open arteries to a lower pressure. This pressure gradient is known as coronary artery perfusion pressure. As diastolic pressure drops, there is a decrease in coronary artery blood flow. The Intra-aortic Balloon Pump (IABP) has the following hemodynamic effects: A. Increases left ventricular pressure B. Increases wedge pressure C. Increases coronary artery perfusion D. Increases afterload - Answer C. Increases coronary artery perfusion Rationale: The major hemodynamic effects of the IABP are increased coronary artery perfusion and decreased afterload. It improves perfusion and decreases the workload of the myocardium. The IABP improves coronary artery perfusion by increasing diastolic pressure, thereby improving coronary perfusion pressure. When listening to heart sounds, the fourth heart sound (S4) occurs: A. After ventricular contraction B. Is best heard with the diaphragm of the stethoscope C. Is a normal finding in children D. During late diastole when the atria contracts - Answer D. During late diastole when the atria contracts Rationale: The presence of the extra heart sound S4 signifies a poorly compliant (stiff) left ventricle. An S4 is also called an atria heart sound since it occurs at the end of diastolic filling when the atria contracts and fully fills the left ventricle. Known as atrial kick, this filling is important to cardiac output. When the left ventricle is stiff (decreased compliance—with long term hypertension, aortic stenosis, or with acute STEMI) the atrial has to pump harder to move blood from the atria to the ventricle causing a turbulent blood flow and causing the extra heart sound. This heart sound is always pathologic. The pathologic changes found on the 12 Lead ECG that indicates myocardial ischemia are: A. ST elevationB. ST segment depression and T wave elevation C. Q wave formation D. ST segment depression and T wave inversion - Answer D. ST segment depression and T wave inversion Rationale: Myocardial ischemia changes the repolarization of the ventricular muscle and that change is seen on the 12 Lead ECG as ST segment depression and T wave inversion. ST segment depression and T wave inversion demonstrates subendocardial ischemia—the inter most layer of muscle in the myocardium. A patient presents in acute distress with rales ½ the way up bilaterally, extremities are cool and wet, elevated JVD, oxygen saturations are 95% down from 99% and complains of shortness of breath. Which assessment corresponds to the patient's cardiac status? A. No pulmonary congestion, normal perfusion B. Pulmonary congestion, normal perfusion C. Pulmonary congestion, low perfusion D. No pulmonary congestion, low perfusion - Answer C. Pulmonary congestion, low perfusion