[Phonocardiographic and Doppler echocardiographic study on the mechanism of the presystolic murmur in mitral stenosis, especially the relationship to mitral inflow dynamics].
The cause of the "presystolic murmur" in mitral stenosis was investigated by phonocardiography and continuous wave Doppler echocardiography in 31 patients with mitral stenosis and sinus rhythm classified into two groups: 18 patients with and 13 without "presystolic murmur". 1. The "presystolic murmur" group demonstrated high frequency vibrations preceding the first heart sound coinciding with the initial low frequency component of the first heart sound recorded at the apex in both groups. 2. There were two types of "presystolic murmur": The first type observed in three of the 18 patients occurred during the accelerated phase of the atrial (A) wave of mitral inflow signals and lasted until the first heart sound. The A wave velocity in mitral inflow signals was high at the onset and peak, and rapidly decreased after the peak. The second type observed in 15 patients occurred during the decelerated phase of the A wave and lasted until the first heart sound. The A wave velocity in mitral inflow signals was low at the onset, but high at the peak and rapidly decreased after the peak. 3. The mitral orifice area tended to be smaller in all patients with "presystolic murmur". The peak flow velocity, deceleration rate of the A wave, and maximal pressure gradient across the mitral valve during atrial contraction were significantly increased in all patients with "presystolic murmur". 4. Five patients with newly developed "presystolic murmur" after amyl nitrite inhalation had an increased initial low frequency component of the first heart sound coinciding with the latter half of "presystolic murmur". The rate of increase in the peak flow velocity and the deceleration rate of the A wave were significantly larger and the maximal atrioventricular pressure gradient during atrial contraction tended to be larger in these five patients than those in five who did not develop "presystolic murmur". 5. The peak flow velocity, deceleration rate of the A wave and the maximal atrioventricular pressure gradient during atrial contraction had increased 1 year later compared with those immediately after cardioversion of atrial fibrillation, and newly developed "presystolic murmur" appeared according to the recovery of left atrial mechanical function. These results suggest that the latter half of "presystolic murmur" originates from augmentation and prolongation of the initial low frequency component of the first heart sound up to the audible range caused by the sudden deceleration of mitral inflow velocity due to left ventricular contraction, and that the early half of "presystolic murmur" is the atriosystolic murmur produced by the increase in mitral inflow velocity during atrial contraction.
Tabata
T
T
Second Department of Internal Medicine, University of Tokushima School of Medicine.
Fukuda
N
N
Iuchi
A
A
Oki
T
T
D001783:Blood Flow Velocity; D015150:Echocardiography, Doppler; D005260:Female; D006347:Heart Sounds / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000503:physiopathology*; D008946:Mitral Valve Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D010701:Phonocardiography; D013599:Systole