Heart sounds in mitral stenosis
S1-The first heart sound is usually accentuated and it is slightly delayed in mitral stenosis.
S2-P2 the pulmonary component may be accentuated and A2 and P2 the two components of second heart sound are closely split.
Opening snap
Opening snap is an abnormal auscultatory finding in mitral stenosis. It usually follows the aortic component of second heart sound by 0.05–0.12 s. It is best heard at or just medial to apex of heart and most readily audible in expiration.
Significance of opening snap is that the time interval between the aortic component (A2) and the opening snap depend upon the severity of mitral stenosis. The time interval varies inversely with the severity of the MS.
Murmur of mitral stenosis
The OS is followed by a diastolic murmur in mitral stenosis. It is a low-pitched, rumbling, diastolic murmur, which is heard best at the apex with the patient in the left lateral recumbent position .
The murmur is accentuated by mild exercise (such as a few rapid sit-ups ) that is carried out just before auscultation.
The duration of this diastolic murmur correlates with the severity of the mitral stenosis in patients with preserved cardiac output.
There is a presystolic accentuation of murmur in patients with sinus rhythm, the murmur often reappears or it becomes louder during atrial systole.
Sometimes a soft, grade I or II/VI systolic murmurs may be heard at the apex or along the left sternal border in pure MS and do not necessarily signify the presence of mitral regurgitation.
Auscultatory findings in mitral stenosis due to associated lesions
If the patient develop severe pulmonary hypertension, a pansystolic murmur may be produced due to functional TR, this may be audible along the left sternal border and is louder during inspiration and diminishes during forced expiration. This phenomenon is called Carvallo’s sign.
When the cardiac output is markedly decreased in mitral stenosis, the typical auscultatory findings, including the diastolic rumbling murmur, may not be detectable. This is called silent MS, but they reappear if the cardiac output is restored.
The Graham Steell murmur of PR, is a high-pitched, diastolic, decrescendo blowing murmur heard along the left sternal border. This murmur occur due to dilatation of the pulmonary valve ring and is seen in patients with mitral valve disease and severe pulmonary hypertension.
