Section 3. Heart and Blood Vessel Disorders

Chapter 28. Heart Valve Disorders

Topics: Introduction | Mitral Regurgitation | Mitral Valve Prolapse | Mitral Stenosis | Aortic Regurgitation | Aortic Stenosis | Tricuspid Regurgitation | Tricuspid Stenosis | Pulmonary Stenosis

Introduction

Heart valves regulate the flow of blood through the heart's four chambers--two small, round upper chambers (atria) and two larger, cone-shaped lower chambers (ventricles (see Section 3, Chapter 20)). Each ventricle has a one-way "in" (inlet) valve and a one-way "out" (outlet) valve. In the right ventricle, the inlet valve is the tricuspid valve, which opens from the right atrium, and the outlet valve is the pulmonary (pulmonic) valve, which opens into the pulmonary arteries. In the left ventricle, the inlet valve is the mitral valve, which opens from the left atrium, and the outlet valve is the aortic valve, which opens into the aorta. Each valve consists of flaps (cusps or leaflets), which open and close like one-way swinging doors.

See the figure Understanding Stenosis and Regurgitation.

The heart valves can malfunction either by leaking (causing regurgitation) or by not opening adequately and thus partially blocking the flow of blood through the valve (causing stenosis). Either problem can greatly interfere with the heart's ability to pump blood. Sometimes a valve has both problems.