Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.
Heart Rhythm. 2011 Jan;8(1):101-8. doi: 10.1016/j.hrthm.2010.10.018. Epub 2010 Oct 19.
Defibrillation therapy for atrial fibrillation (AF) and flutter (AFl) is limited by pain induced by high-energy shocks. Thus, lowering the defibrillation energy for AFl/AF is desirable.
In this study we applied low-voltage multiple-shock defibrillation therapy in a rabbit model of atrial tachyarrhythmias comparing its efficacy to single shocks and antitachycardia pacing (ATP).
Optical mapping was performed in Langendorff-perfused rabbit hearts (n = 18). Acetylcholine (7 ± 5 to 17 ± 16 μM) was administered to promote sustained AFl and AF, respectively. Single and multiple monophasic shocks were applied within 1 or 2 cycle lengths (CLs) of the arrhythmia.
We observed AFl (CL = 83 ± 15 ms, n = 17) and AF (CL = 50 ± 8 ms, n = 11). ATP had a success rate of 66.7% in the case of AFl, but no success with AF (n = 9). Low-voltage multiple shocks had 100% success for both arrhythmias. Multiple low-voltage shocks terminated AFl at 0.86 ± 0.73 V/cm (within 1 CL) and 0.28 ± 0.13 V/cm (within 2 CLs), as compared with single shocks at 2.12 ± 1.31 V/cm (P < .001) and AF at 3.46 ± 3 V/cm (within 1 CL), as compared with single shocks at 6.83 ± 3.12 V/cm (P =.06). No ventricular arrhythmias were induced. Optical mapping revealed that termination of AFl was achieved by a properly timed, local shock-induced wave that collides with the arrhythmia wavefront, whereas AF required the majority of atrial tissue to be excited and reset for termination.
Low-voltage multiple-shock therapy terminates AFl and AF with different mechanisms and thresholds based on spatiotemporal characteristics of the arrhythmias.
由于高能电击引起的疼痛，房颤（AF）和房扑（AFl）的除颤治疗受到限制。因此，降低 AFl/AF 的除颤能量是理想的。
本研究在兔房性心动过速模型中应用低电压多次电击除颤治疗，比较其与单次电击和抗心动过速起搏（ATP）的疗效。
在 Langendorff 灌注兔心中进行光学标测（n = 18）。分别给予乙酰胆碱（7 ± 5 至 17 ± 16 μM）以促进持续的 AFl 和 AF。在心律失常的 1 或 2 个心动周期（CL）内应用单相单极和多极电击。
我们观察到 AFl（CL = 83 ± 15 ms，n = 17）和 AF（CL = 50 ± 8 ms，n = 11）。ATP 对 AFl 的成功率为 66.7%，但对 AF 无效（n = 9）。低电压多次电击对两种心律失常均 100%有效。与单次电击相比，多极低电压电击终止 AFl 的阈值分别为 0.86 ± 0.73 V/cm（在 1 个 CL 内）和 0.28 ± 0.13 V/cm（在 2 个 CL 内），而终止 AF 的阈值分别为 2.12 ± 1.31 V/cm（P <.001）和 3.46 ± 3 V/cm（在 1 个 CL 内），与 6.83 ± 3.12 V/cm（P =.06）相比。未诱发心室心律失常。光学标测显示，AFl 的终止是通过一个适时的、局部电击诱导的波与心律失常波前碰撞来实现的，而 AF 需要大部分心房组织兴奋和重置才能终止。
低电压多次电击治疗通过心律失常的时空特征，以不同的机制和阈值终止 AFl 和 AF。
