| Abstract: | The effects of verapamil on the diastolic function and regional asynchrony of the left ventricle were echocardiographically investigated in 37 patients with hypertrophic non-obstructive cardiomyopathy (HCM). Before and 20 min after the intravenous administration of verapamil (0.1 mg/kg), blood pressure (BP), heart rate (HR), transmitral pulsed Doppler indices (R, A, A/R), M-mode echo indices (Dd, Ds, %FS) and the echo-phonocardiographic index (isovolumic relaxation time; IRT) were measured. We also measured the rapid extension times of the posterior walls at the chordae and papillary muscle level [Tc(pw), Tp(pw)] as the indices of regional diastolic function, and their difference [Tp-c(pw)] was used as the index of diastolic asynchrony. Before verapamil administration, the HCM patients had significantly larger A, A/R, IRT and Tp-c(pw) and smaller R than did 20 healthy controls, but showed no significant differences in HR, BP, Dd, Ds and %FS. After verapamil injection, R increased and A, A/R, IRT, Tp-c(pw) decreased significantly without any changes in BP and HR. The increment of R (delta R) correlated significantly with the decrement of Tp-c(pw) (r = -0.66, p less than 0.001). According to the value of delta R/R, 37 patients with HCM were categorized in 2 groups (19 responders with delta R/R greater than or equal to 10% and 18 non-responders with delta R/R less than 10%). The responders had smaller R and larger A/R, IRT and Tp-c(pw) before verapamil administration than did the non-responders. Verapamil increased R, Dd, Ds and decreased A, A/R and Tp-c(pw) in the responders, but not in the non-responders. These results suggested that verapamil might improve left ventricular diastolic function in HCM patients through the improvement of left ventricular diastolic asynchrony. |
