胺碘酮对犬正常心肌与肥厚心肌跨室壁不应期离散的影响

目的探讨胺碘酮对正常心肌与肥厚心肌跨室壁不应期离散(TDR)的影响。方法采用特制电极直接测量在体三层心肌的有效不应期(ERP)的方法,观察胺碘酮对犬正常心肌和肥厚心肌三层心肌ERP和TDR的影响。结果犬正常心肌在用胺碘酮前后三层之间的ERP无显著差异。犬肥厚心肌各层的ERP之间有显著性差异,应用胺碘酮后TDR明显缩小。正常心肌各层的TDR在循环长度改变时其数值差异无显著性,而在肥厚心肌TDR的差异显著。结论犬肥厚心肌的三层心肌间存在显著的TDR。胺碘酮可使肥厚心肌三层心肌的TDR减小。长-短间期或短-长间期刺激可使肥厚心肌的TDR增大,应用胺碘酮后,TDR无显著差异。

Effect of amiodarone on transmural dispersion of ventricular effective refractory periods among myocardial layers in the normal and hypertrophic canine heart

Objective To investigate the effects of amiodarone on transmural dispersion of ventricular effective refractory periods (TDR) in the normal and hypertrophic canine heart in vivo. Methods By using the programmed stimulation protocol, the effective refractory periods (ERP) of epicardium (Epi), midmyocardium (Mid), endocardium (Endo) and TDR of the three layers were measured by inserting specially-designed electrodes into the three myocardial layers before and after mainlining of amiodarone in the two groups. Result No significant TDR was observed in the three layers before and after mainlining amiodarone in the normal group. In contrast, ERP of all the three layers was prolonged in the hypertrophic heart, while the TDR was reduced significantly after mainlining of amiodarone. The TDR was significantly increased in the hypertrophic heart but not in the normal heart using “long-short” and “short-long” interval stimulation technique. Conclusion The differences in TDR among the three layers were significant in hypertrophic heart. The TDR was significantly decreased in hypertrophic heart after using amiodarone. The programmed extrastimulus technique of “long-short” and “short-long” intervals increased the TDR in the hypertrophic heart.