Mitral regurgitation and left ventricular outflow tract obstruction in hypertrophic cardiomyopathy. Analysis by Doppler echocardiography.

: In a group of five patients with asymmetric septal hypertrophy, the presence of the mitral regurgitation and the left ventricular outflow tract gradient were studied by the Doppler echocardiographic technique. By means of Bernoulli's formula 4V2 = P1-P2, left ventricular maximal systolic pressure was assessed using mitral regurgitant and left ventricular outflow tract jets. Aortic systolic and diastolic blood pressures were measured by cuff sphygmomanometry, and simultaneous carotid pulse tracings were recorded. All patients had outflow tract pressure gradients (peak 84 +/- 11.7 mmHg) and mild mitral regurgitation. Continuous wave Doppler study recorded peak flow velocities in the outflow tract (4.6 +/- 0.26 m/sec) and mitral regurgitant (6.5 +/- 0.51 m/sec) jets. The values for ventricular systolic pressures by both methods were similar (180 +/- 24.2 vs 186 +/- 13.5 mmHg). This study confirms the presence of mitral regurgitation and actual obstruction in hypertrophic cardiomyopathy with asymmetric septal hypertrophy.