A 55-year-old man comes to the emergency department with recurrent episodes of retrosternal chest pain. The episodes occur during physical activity, usually when he climbs stairs or walks uphill. The patient has no known medical problems and does not use tobacco, alcohol, or illicit drugs. He is given a sublingual tablet and reports rapid relief of the pain. This drug most likely improved this patient's symptoms by causing which of the following hemodynamic changes?

Question

A 55-year-old man comes to the emergency department with recurrent episodes of retrosternal chest pain.  The episodes occur during physical activity, usually when he climbs stairs or walks uphill.  The patient has no known medical problems and does not use tobacco, alcohol, or illicit drugs.  He is given a sublingual tablet and reports rapid relief of the pain.  This drug most likely improved this patient's symptoms by causing which of the following hemodynamic changes?

Quizplus · Accepted Answer

11ec160b_3b96_c30b_9249_83398906ae33_MD0001_00 This patient has a classic presentation of chronic stable angina, which is characterized by chest pain that occurs with activity and is relieved with rest or sublingual nitroglycerin. Nitrates exert their effect by direct vascular smooth muscle relaxation that results in: This results in decreased myocardial oxygen demand, leading to improved exercise tolerance and relief of angina symptoms. (Choices A and D) Nitrates dilate the large epicardial arteries more than the smaller resistance vessels (eg, arterioles). Furthermore, coronary arterioles in an area of flow-limited stenosis are typically dilated maximally to maintain resting blood flow, limiting the ability of nitrates to significantly increase blood flow in stenotic coronary arteries. (Choice B) Nitrates do not directly affect cardiac chronotropy and/or inotropy but can increase the heart rate as a reflex response to reduced blood pressure. Beta blockers and nondihydropyridine calcium channel blockers may exert their antianginal effect in part via a decrease in the heart rate (negative chronotropic effect). (Choice E) Coronary perfusion pressure is the pressure gradient that drives coronary perfusion during diastole and is equal to the difference between the end-diastolic aortic pressure and the left ventricular end-diastolic pressure. Nitrates may slightly reduce coronary perfusion pressure as they lower systemic arterial pressure; however, the overall hemodynamic effects of nitrates are beneficial during angina as they lead to decreased myocardial oxygen demand. Educational objective: Sublingual nitroglycerin is used for rapid symptom relief in patients with stable angina. The primary anti-ischemic effect of nitrates is mediated by venodilation with a decrease in left ventricular end-diastolic volume and wall stress, resulting in decreased myocardial oxygen demand and relief of angina symptoms. __________ References: Hemodynamic effects of nitroglycerin and long-acting nitrates. (http://www.ncbi.nlm.nih.gov/pubmed/3925741) Beneficial actions of nitrates in cardiovascular disease. (http://www.ncbi.nlm.nih.gov/pubmed/8638524)

A 55-Year-Old Man Comes to the Emergency Department with Recurrent