Cardiovascular Physiology Concepts
                                    Richard E. Klabunde, Ph.D.

Mitral Stenosis

The following describes changes that occur in the left ventricular pressure-volume loop when there is mitral stenosis. Mitral stenosis (red pressure-volume loop in figure) impairs left ventricular filling so that there is a decrease in end-diastolic volume (preload). This leads to a decrease in stroke volume by the Frank-Starling mechanism and a fall in cardiac output and aortic pressure. This reduction in afterload (particularly aortic diastolic pressure) enables the end-systolic volume to decrease slightly, but not enough to overcome the decline in end-diastolic volume. Therefore, because end-diastolic volume decreases more than end-systolic volume decreases, the stroke volume (shown as the width of the loop) decreases.

The changes described above and shown in the figure do not include cardiac and systemic compensatory mechanisms (e.g., systemic vasoconstriction, increased blood volume, and increased heart rate and inotropy) that attempt to maintain cardiac output and arterial pressure.

RK Revised 04/05/07

DISCLAIMER: These materials are for educational purposes only, and are not a source of medical decision-making advice.

© 1999-2008 Richard E. Klabunde, all rights reserved.