[Effects of beta-blockers and Ca antagonists on diastolic function of the hypertrophied left ventricle: an echocardiographic study].

Left ventricular (LV) relaxation was studied in patients with hypertensive heart disease with LV hypertrophy (HHD, n = 25) and hypertrophic cardiomyopathy (HCM, n = 9), and these data were compared with that of normal controls (n = 20). The effects of oral administration of propranolol (n = 11), pindolol (n = 3), nifedipine (n = 6) and diltiazem (n = 5) in patients with HHD and that of propranolol (n = 9) in patients with HCM were also studied. Isovolumic relaxation time (IRT) was measured using dual M-mode echocardiography and peak normalized rate of change of the LV cavity in early diastole (peak dD/dt/D) was calculated by M-mode echocardiography using a digitizer and microcomputer system. IRT was significantly longer in HHD (112 +/- 24 msec, p less than 0.001) and in HCM (85 +/- 40 msec, p less than 0.05) compared with that of normal subjects (64 +/- 24 msec). The normal value of peak dD/dt/D was 3.8 +/- 0.7 sec-1, and it was significantly lower in HHD (2.7 +/- 0.8 sec-1, p less than 0.001). It was also lower in HCM (3.2 +/- 0.8 sec-1), but without a statistical significance. In HHD there was a significant relationship (r = -0.611, p less than 0.01) between peak dD/dt/D and wall thickness of the LV (interventricular septum + LV posterior wall). There was no significant change in IRT before and after the administration of beta-blockers and calcium antagonists except nifedipine in HHD (before: 116 +/- 28 msec, after: 80 +/- 14 msec, p less than 0.005). It was probably due to the effect of an accompanied decrease in heart rate. However, peak dD/dt/D was significantly increased in both HHD and HCM groups after the administration of propranolol, pindolol, nifedipine and diltiazem. These data show that LV relaxation is abnormal in the hypertrophied LV. Although the genesis of this abnormality is not clear, there seems to be a close relationship between the relaxation abnormality and increased LV mass in HHD. Oral administration of propranolol, pindolol and diltiazem for patients with HHD and propranolol for patients with HCM seems to improve the abnormal LV relaxation of each disease.