Mitral Stenosis Auscultation Characteristics

Mitral stenosis produces distinct heart sounds and murmurs that are key indicators for clinical diagnosis. Understanding these auscultatory features helps in identifying the condition and assessing its severity.

First Heart Sound and Opening Snap

In cases where the mitral valve leaflets remain pliable and elastic, the first heart sound (S1) is typically loud and accentuated at the cardiac apex. An opening snap of the mitral valve may also be present, producing a sharp, tapping-like sound shortly after the second heart sound (S2). This snap indicates that the valve opens abruptly due to elevated left atrial pressure. However, if the valve becomes calcified and rigid, this characteristic opening snap disappears.

Pulmonary Hypertension and Second Heart Sound Changes

When mitral stenosis is accompanied by pulmonary hypertension, the second heart sound (S2) becomes accentuated at the pulmonary valve area. This is often followed by a wide or fixed splitting of S2, which reflects the increased pressure load on the right side of the heart.

Characteristics of the Diastolic Murmur

The hallmark auscultatory finding in mitral stenosis is a low-pitched, rumbling diastolic murmur heard best at the apex. This murmur usually occurs during mid to late diastole and tends to increase in intensity (crescendo pattern). It is more pronounced when the patient is in the left lateral decubitus position. Physical activity or forced expiration can enhance the murmur's audibility. In some cases, a diastolic thrill may accompany the murmur, indicating significant flow turbulence.

Additional Auscultatory Findings

In advanced stages with severe pulmonary hypertension, relative pulmonary regurgitation may occur. This results in a high-pitched, decrescendo diastolic murmur—often described as a "blowing" or "sighing" sound—best heard at the left upper sternal border (second intercostal space).

Furthermore, as right ventricular dilation progresses due to increased pulmonary pressure, functional tricuspid regurgitation may develop. This manifests as a holosystolic, blowing murmur detected at the lower left sternal border (fourth to fifth intercostal space), indicating ineffective tricuspid valve closure during systole.