Diastolic abnormalities in patients with hypertrophic cardiomyopathy: relation to magnitude of left ventricular hypertrophy.

To investigate the relationship between diastolic abnormalities and left ventricular hypertrophy, 52 patients with hypertrophic cardiomyopathy (HCM) and 22 normal subjects were studied with digitized M mode echocardiography and two-dimensional echocardiography. Echocardiographic indexes of diastolic function were compared in patients with different extent of left ventricular hypertrophy. Time interval from minimum left ventricular internal dimension to mitral valve opening and time to peak rate of increase in left ventricular internal dimension were significantly prolonged (80 +/- 31 and 100 +/- 37 msec, respectively) in patients with HCM and the most extensive left ventricular hypertrophy compared with those in patients with mild left ventricular hypertrophy (59 +/- 25 and 74 +/- 34 msec, respectively; p less than .01). Furthermore, peak rate of posterior wall diastolic excursion was significantly reduced in those patients with HCM and posterior wall hypertrophy (8.3 +/- 4.0 cm/sec) compared with that in patients with HCM but normal posterior wall thickness (11.2 +/- 3.4 cm/sec; p less than .002). However, abnormal M mode echocardiographic indexes of diastolic function were also identified in a substantial proportion of patients (i.e., 73%) with HCM and only mild left ventricular hypertrophy. In these patients, time interval from minimum left ventricular internal dimension to mitral valve opening (59 +/- 25 msec), peak rate (12 +/- 4 cm/sec), and time to peak rate of increase in left ventricular internal dimension (74 +/- 34 msec) were significantly different from normal (25 +/- 12 msec, 21 +/- 3 cm/sec, and 49 +/- 12 msec, respectively; p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)