长时间心室颤动除颤成功后早期复发的电生理作用机制

The electrophysiological mechanism of early refibrillation after successful defibrillation for long duration ventricular fibrillation.

目的通过整体左室心内膜电生理标测研究长时间心室颤动(简称室颤)除颤成功后室颤早期复发的电生理作用机制。方法将64极伞状电极经颈动脉逆行植入6只正常比格犬的左室行电生理标测。通过快速电刺激,分别诱发20 s短时间室颤和7 min长时间室颤,随后给予体内双相波除颤。比较不同时间室颤除颤成功后最早激动时间和室颤复发率。利用电生理激动图分析室颤复发时的激动特征。结果 6只动物累计短时间室颤除颤成功24次,无1次室颤复发。7 min长时间室颤除颤成功6次,每次成功除颤后至少1次室颤早期复发,观察时间内累计复发14次,平均每只动物发作2.3±1.9次,与短时间室颤相比,室颤复发率显著升高(P<0.01)。与短时间室颤相比,长时间室颤除颤后最早激动时间显著延长(5 125±3 373 ms vs 322±166 ms,P<0.01)。14次复发室颤前,均有室性早搏。电生理标测提示,10次复发源自间隔部附近的局灶活动。结论无器质性心脏疾病的长时间室颤除颤成功后室颤早期复发十分常见,但未见于短时间室颤,提示长时间室颤本身可致室颤复发,其复发的起始电生理机制可能与局灶兴奋相关。

Objective The aim of this study is to investigate the electrophysiological mechanism of early refibrillation after successful defibrillation for long duration ventrieular fibrillation （LDVF） by global left ventricular （LV） endoeardial mapping. Methods A basket catheter containing 64 electrodes used for global endocardium electrical mapping were de- ployed into LV of six beagles. Twenty seconds short duration VF （SDVF） and 7 minutes LDVF were electrically induced and terminated by internal defibrillation with biphasie shocks. Early VF recurrence and earliest postshoek activation follow- ing successful defibrillation were compared between SDVF and LDVF respectively. Isochronal maps were used to analyze the recurrence of VF activation. Results There was no refibrillation episode of 24 successful shocks for SDVF. At least one refibrillation episode followed 7 minutes LDVF in six animals. 2.3 ± 1.9 refibrillation episodes per animal after 7 minutes LDVF were observed. The VF recurrence of LDVF was significantly higher than that of SDVF （ P 〈 0.01 ）. Compared with SDVF, earliest postshock interval of LDVF was significantly prolonged （5 125± 3 373 ms vs 322 ± 166 ms, P 〈 0.01 ）. Ventricular premature was seen before the 14 episodes of refibrillation. 71% early VF recurrence focally arose from near ventricular septum. Conclusions Early VF recurrence is commonly found after LDVF, but not after SDVF in normal hearts, suggesting that LDVF by itself can cause refibrillation without requiring previously diseased hearts. Foci from near ventricular septum may play a role in this refibrillation.