DiPalma Joseph R, Kutalek Steven P, Eisen Howard, Kresh J Yasha, Pelleg Amir
Drexel University College of Medicine, Philadelphia, PA 19102-1192, USA.
Am J Ther. 2008 Mar-Apr;15(2):190-5. doi: 10.1097/MJT.0b013e31815adb63.
Cardiac resynchronization therapy (CRT) in patients with heart failure and bundle branch block (BBB) improves regional muscle mechanics and mechanical pump function of the heart. In addition, modulation of wall motion timing and contraction can exert an antiarrhythmic effect, reducing the potential of sudden cardiac death. This effect of CRT could also be attributed to the improvement in excitation-contraction coupling, mechanical synchronization, and improved myocardial perfusion. However, it can be hypothesized that the BBB results in a concealed reentry, in which a delayed depolarization wave re-enters during phase two of the action potential. This concealed phase 2 reentry can lead to early after depolarizations and cardiac arrhythmias. By synchronizing the two ventricles, CRT eliminates the reentry substrate and the resulting arrhythmias. This hypothesis and the potential arrhythmogenic effects of CRT are discussed with regard to ventricular remodeling and mechano-electrical feedback in this setting.
心力衰竭合并束支传导阻滞（BBB）患者的心脏再同步治疗（CRT）可改善心脏局部肌肉力学和机械泵功能。此外，对壁运动时间和收缩的调节可发挥抗心律失常作用，降低心源性猝死的可能性。CRT的这种作用也可归因于兴奋-收缩偶联的改善、机械同步性的提高以及心肌灌注的改善。然而，可以推测BBB会导致隐匿性折返，即延迟的去极化波在动作电位的第2期重新进入。这种隐匿性2期折返可导致早期后去极化和心律失常。通过使两个心室同步，CRT消除了折返基质及由此产生的心律失常。在此背景下，就心室重构和机械电反馈讨论了这一假说及CRT潜在的致心律失常作用。
