四氢巴马汀对在体犬跨室壁复极离散度的影响

从跨室壁复极离散度(TDR)的角度研究左旋四氢巴马汀(L-THP)的电生理作用。采用自制电极同步记录在体犬左室三层心肌细胞的单向动作电位(MAP),观察静脉注射L-THP前后动作电位时程(APD)、振幅(APA)、TDR及各层心肌有效不应期(ERP)的变化。结果:应用L-THP后三层心肌的动作电位复极90%的时程均延长(内、中、外层心肌分别为189.67±23.29msvs182.83±23.70ms、194.67±24.12msvs192.17±24.49ms和185.08±24.53msvs173.42±22.06ms,P均<0.01),内、外层心肌ERP显著增加(分别为164.54±20.53msvs159.08±20.08ms、161.60±21.28msvs150.99±18.93ms,P<0.01)、TDR降低(9.58±2.94msvs18.75±3.77ms,P<0.01),对APA无明显影响。结论:L-THP降低心室肌的TDR,延长心室内、外膜心肌细胞的ERP。

Effects of L-tetrahydropalmatine on the Transmural Dispersion of Repolarization of Canine in Vivo

To investigate the electrophysiological effects of L-tetrahydropalmatine (L-THP) on transmural di spersion of repolarization (TDR), monophasic action potential (MAP) from the sub-endocar dium (sub-Endo), mid-myocardial (Mid) and sub-epicardium (sub-Epi) of canine left ventricular anterior wall was recorded with a self-made electrodes simultaneously. The dive rsification of TDR, the action potential duration (APD), the amplitude of action potential (APA) and the effective refractory period (ERP) were compared before and after the intravenous injection of L-THP. Results: After the intravenous injection of L-THP,APD_ 90 of sub-Endo, Mid and sub-Epi myocardium were significantly increased (189.67± 23.29 ms vs 182.83±23.70 ms, 194.67±24.12 ms vs 192.17±24.49 ms and 185.08±2 4.53 ms vs 173.42±22.06 ms respectively,all P<0.01 ). ERP in the sub-Endo and sub-Epi was significantly increased( 164.54±20.53 ms vs 159.08±20.08 ms,161.60± 21.28 ms vs 150.99±18.93 ms respectively,P<0.01),but TDR decreased (9.58± 2.94 ms vs 18.75±3.77ms,P<0.01) significantly, and no significant impact o n the APA of three myocardium layer could be detected. Conclusions: TDR of ventricular myocardium can be decreased and ERP of both sub-Endo and sub -Epi myocardium can be prolonged by L-THP.