MEDizzy - A cardiac catheterization is performed on a 39-year-old man

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Cardiovascular Physiology

A cardiac catheterization is performed on a 39-year-old man who presents with angina. The left ventricular pressure-volume curve shows a decreased stroke volume and ejection fraction. Which of the following mechanisms may compromise stroke volume following myocardial infarction?

ExplanationStroke volume is determined by preload, afterload, and contractility. Increasing heart rate decreases the time for filling during diastole and may decrease preload and therefore stroke volume. Increasing preload by increasing central venous pressure will increase stroke volume. Similarly, decreasing afterload by decreasing total peripheral resistance or systemic blood pressure will cause an increase in stroke volume. Increasing contractility will also increase stroke volume.