Author Question: ST segment monitoring for ischemia has gained increasing importance with the advent of thrombolytic ... (Read 53 times)

fox · **on:** Jun 25, 2018

ST segment monitoring for ischemia has gained increasing importance with the advent of thrombolytic therapy. The most accurate method for monitoring the existence of true ischemic changes is

a. T-wave inversion in leads overlying the ischemia.
b. ST segment depression in leads overlying the ischemia.
c. adjusting the gain control on bedside monitoring for best visualization.
d. 12-lead ECG for confirmation.

Question 2

Which of the following mechanisms is responsible for the augmentation of coronary arterial blood flow and increased myocardial oxygen supply seen with the intra-aortic balloon pump?

a. The vacuum created in the aorta as a result of balloon deflation
b. Diastolic inflation with retrograde perfusion
c. Forward flow to the peripheral circulation
d. Inflation during systole to augment blood pressure

bulacsom · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

D
Cardiac biomarkers are proteins that are released from damaged myocardial cells. The initial elevation of cTnI, cTnT, and CK-MB occurs 3 to 6 hours after the acute myocardial damage. This means that if an individual comes to the emergency department as soon as chest pain is experienced, the biomarkers will not have risen. For this reason, it is clinical practice to diagnose an acute myocardial infarction by 12-lead electrocardiography and clinical symptoms without waiting for elevation of cardiac biomarkers.

Answer to Question 2

B
The blood volume in the aorta below the level of the balloon is propelled forward toward the peripheral vascular system, which may enhance renal perfusion. Subsequently, the deflation of the balloon just before the opening of the aortic valve creates a potential space or vacuum in the aorta, toward which blood flows unimpeded during ventricular ejection. This decreased resistance to left ventricular ejection, or decreased afterload, facilitates ventricular emptying and reduces myocardial oxygen demands.