Valvular Disease

Heart valves maintain forward blood flow by opening with minimal resistance and closing without a significant backward leak. Stenosis obstructs forward flow. The chamber behind the narrowed valve must generate greater pressure, producing pressure overload and usually concentric hypertrophy. Regurgitation allows blood to move backward, so the affected chamber handles an excessive volume and gradually dilates. These adaptations preserve output for a time; later, contractile reserve falls and heart failure develops. Valvular disease may be isolated, involve several valves, or coexist with atrial fibrillation, coronary disease, pulmonary hypertension, or ventricular dysfunction. The same numerical lesion can carry different clinical meaning depending on symptoms, ventricular response, pulmonary pressures, valve anatomy, and flow state. The clinical stages are: - Stage A — at risk: risk factors or a condition that may eventually damage a valve, without established significant dysfunction. - Stage B — progressive: established mild-to-moderate valve dysfunction or evolving structural disease. - Stage C — asymptomatic severe: severe dysfunction is present, but the patient denies limiting symptoms. Objective ventricular or pulmonary consequences may still be developing. - Stage D — symptomatic...