A 75-Year-Old Woman Comes to the Physician Because of Progressive

A 75-year-old woman comes to the physician because of progressive shortness of breath with exertion for the past 2 days. She is unable to walk further than a few houses down the street or climb the stairs at her home. She has occasional palpitations and a dry cough. She lives independently with her husband and is capable of doing her household chores. She has hypertension treated with hydrochlorothiazide and amlodipine. Pulse is 72/min, respirations are 20/min, and blood pressure is 145/90 mm Hg. A grade 4/6 holosystolic murmur and an early-diastolic heart sound are heard best at the cardiac apex. Bilateral crackles are heard on pulmonary examination. Which of the following would most likely increase the ratio of forward flow volume to regurgitant flow volume in this patient?

A) Decreasing heart rate
B) Decreasing systemic vascular resistance
C) Decreasing venous return to the left ventricle
D) Increasing left ventricular contractility
E) Increasing venous return to the left ventricle