M-mode echocardiogram in hypertrophic cardiomyopathy with dynamic obstruction

In hypertrophic cardiomyopathy there is altered diastolic function, with slow left ventricle relaxation and left atrial (LA) emptying; the aortic (Ao) root diastolic motion is altered so that early rapid posterior motion is not seen until atrial contraction. This pattern is the counterpart of the a-wave dominant diastolic pattern seen by Doppler. The net forward motion of the Ao is adequate, but the timing and distribution have changed. The initial opening of the aortic valve (AV) is normal but shows a prominent midsystolic closure or notch, which coincides with the onset of subaortic obstruction induced by the systolic contact of the mitral valve with the septum; the AV often reopens for the second half of systole.