Systolic time intervals in rheumatic mitral stenosis

Thirty two patients with pure mitral stenosis and twenty normal subjects were studied by M-Mode Echocardiography and systolic time intervals. Preejection period (PEP) was increased in 62 percent of patients in New York Heart Association (NYHA) Class III and IV, compared to 42.9 percent of cases in NYHA class I and II. Left ventricular ejection time (LVET) was abbreviated in 87.5 percent cases in NYHA class III and IV, and in 58.3 percent of cases in NYHA class I and II. PEP/LVET ratio was significantly increased (p less than 0.01) in mitral stenosis (0.42) compared to normal subjects (0.33) while calculated left ventricular ejection fraction (EF) was significantly lower (p less than 0.01) in mitral stenosis (60%) compared to normal subjects (71.55%). It is hypothesized that a rigid "mitral complex" immobilises the posterobasal area of the left ventricle in mitral stenosis thereby impairing left ventricular contraction.