A 77-year-old patient with a history of coronary artery disease and heart failure has arrived in the emergency room with a rapid heart rate and feeling of "impending doom." Based on pathophysiologic principles, the nurse knows the rapid heart rate could
A) decrease renal perfusion and result in the development of ascites.
B) be a result of catecholamines released from SNS that could increase the myocardial oxygen demand.
C) desensitize the $\beta$-adrenergic receptors leading to increase in norepinephrine levels.
D) prolong the electrical firing from the SA node resulting in the development of a heart block.

Question

Quizplus · Accepted Answer

An increase in sympathetic activity by stimulation of the $\beta$-adrenergic receptors of the heart leads to tachycardia, vasoconstriction, and arrhythmias. Acutely, tachycardia ^{significantly increases the workload of the heart, thus increasing myocardial O}2 ^demandand leading to cardiac ischemia, myocyte damage, and decreased contractility.Decreased renal perfusion would activate the RAA system, increasing heart rate and BP further. Ventricular arrhythmias are primarily seen at this stage of HF.

A 77-Year-Old Patient with a History of Coronary Artery Disease β\betaβ

A 77-Year-Old Patient with a History of Coronary Artery Disease $\beta$