Phonocardiographic study in patients with mitral stenosis
In 1911 Weiss and Joachim reported a delay in the onset of the first heart sound in mitral stenosis, and in 1951 Sprague and his associates demonstrated that in patients with mitral stenosis and atrial fibrillation the Q-1 interval varied inversely with previous cardiac cycle length. This was confirmed by Wells in 1954.
The purpose of this study in phonecardiographic avaluation as a quantitative diagnostic method in patients in patients with mitral stenosis.
The Q-1, w-OS intervals and PCG index were used in phonocardiographic evaluation as a predictive value of severity of mitral stenosis in 73 patients with pure or predominant mitral stenosis comparing with the results obtained from cardiac catheterization or from operation.
The following results were obtained:
1. Q-1 intervals are significantly prolonged in patients with mitral stenosis with a mean of 0.105±0.007 second compared with the normal subjects with a mean of 0.068±0.004 second, and roughly correlated with the severity of the mitral stenosis.
2. Opening snap was absent in 26% of all patients(19/73), 23% of patients with pure mitral stenosis and 33.3% of patients with mitral stenosis with mild degree of mitral insufficiency.
3. 2-OS intervals ranged from 0.03 to 0.13 second with an average of 0.089 second inversely related roughly to the severity of mitral stenosis.
4. Phonocardiogram index ranged from -5 to +6. The total number of patients with PCG index +2 or more was 55 and those with PCG index with+1 or less was 18.
5. The correlations of Q-2, 2-OS intervals and PCG index with mitral valvular area(MVA) were not sufficient to utilise for accurate prediction of MVA, however, these intervals could be used to separete patients with severe stenosis from those with mild stenosis.
6. Phonocardiogram estimato of mitral valvular area was correct in around 70% ranging from 55.6% to 80.9%, and there was no apparent superiority of the PCG index over Q-1 interval of 2-OS interval as predictive value of severity of mitral stenosis.
7. All 5 patients taken phonocardiogram after successful valvulotomy showed shortening of Q-1 interval and prologation of 2-OS interval compared with the intervals before the surgery.