Assessment of Left Ventricular Diastolic Function and Effect of Calcium Channel-Blocking Agent on Diastolic Function by Pulsed Doppler Echocardiography in Patients with Hypertrophic Cardiomyopathy

Kim, June Soo; Cho, Myeong Chan; Kim, Young Kwon; Kim, Duk Kyung; Kim, Cheol Ho; Sohn, Dae Won; Choi, Yun Shik; Seo, Jung Don; Lee, Young Woo

Abstract

The symptoms of hypertrophic cardiomyopaty frequently result from impaired left ventricular relaxation, abnormal left ventricular filling, and decreased compliance of left ventricle in spite of normal systolic function. Several studies have suggested that the assessment of transmitral flow velocity waveform with pulsed Doppler echocardiography in patients with hypertrophic cardiomyopathy provide a noninvasive and clinically useful expression of left ventricular diastolic performance. In this study, pulsed Doppler echocardiography was used to measure diastolic indices from transmitral flow velocity waveform and thereby to assess left ventricular diastolic function in 20 patients with hypertrophic cardiomyopathy (14 septal hypertrophy, 3 apical hypertrophy, and 3 concentric hypertrophy). The diastolic indices to measure are isovolumic relaxation time(IVRT), deceleration time(DT), pressure half time(PHT), deceleration of early diastolic flow(DEF), EF slope, peak flow velocity in early diastole(PFVE), peak flow velocity during atrial systole(PFVA), and PFVE/PFVA ratio. The diastolic indices obtained from patients were compared with those in 20 age-matched control subjects without heart disease. The relationship between left ventricular wall thickness index(Th Index) and diastolic indices were evaluated. In addition, the effect of calcium channel-blocking agent on left ventricular diastolic function were evaluated. The results were as follows ; 1) There were no significant differences in RR interval, BP, end-systolic left ventricular dimension, and end-diastolic left ventricular dimension, but significant differences in interventricular septal thickness, posterior wall thickness, and left atrial dimension between hypertrophic group and control group. 2) The systolic index(ejection fraction) showed no significant difference between hypertrophic group and control group. 3) All diastolic indices except PFVA showed significant differences between hypertrophic group and control group. 4) Th Index did not showed a significant correlation with the diastolic indices except PFVE/PFVA. 5) There were no significant changes in RR interval, BP end-systolic left ventricular dimension, end-diastolic left ventricular dimension, left atrial dimension, and ejection fraction between medication and drug withdrawal. IVRT significantly increased after drug withdrawal. But other diastolic indices showed no significant changes after drug withdrawal. According to above results the assessment of left ventricular diastolic function by pulsed Doppler echocardiography was a clinically useful method in detecting diastolic dysfunction in patients with hypertrophic cardiomyopathy. Calcium channel-blocking agent may have beneficial effect in improving left ventricular diastolic function in patients with hypertrophic cardiomyopathy.