Low-Tilt Monophasic and Biphasic Waveforms Compared with Standard Biphasic Waveforms in the Transvenous Defibrillation of Ventricular Fibrillation

作者：Bennett Johan R^*; Darragh Karen M; Walsh Simon J; Allen Desmond J; Scott Michael; Stevenson Michael; Adgey Jennifer A A; Anderson John M C J; Manoharan Ganesh

来源：Pacing and Clinical Electrophysiology, 2014, 37(3): 279-289.

DOI：10.1111/pace.12266

• ventricular fibrillation
• defibrillation
• low tilt
• waveform

BackgroundCommercially available implantable defibrillators utilize a high-tilt waveform. Studies in atrial fibrillation and transthoracic defibrillation of ventricular fibrillation (VF) have shown improved defibrillation efficacy using low-tilt (LT) waveforms. We investigated the feasibility, efficacy, and safety of a LT waveform in the transvenous defibrillation of VF and hypothesized that it would be more efficacious than standard tilted biphasic (STB) waveforms. %26lt;br%26gt;Methods and ResultsThe investigation was performed in four phases in a porcine model: an efficacy study of LT monophasic waveforms (n= 9), an efficacy study of LT biphasic waveforms (n= 9), a comparison study between the most successful LT waveforms and clinically available STB waveforms (n= 15), and a safety study (n= 9). A total of 1,056 shocks were delivered (phase 1: 288, phase 2: 288, phase 3: 480). The LT biphasic 8/4-ms waveform was significantly more likely to successfully defibrillate than the LT monophasic and STB waveforms with an odds ratio of 122.3 (95% confidence interval: 32.5, 460.2, P%26lt; 0.001). The calculated defibrillation threshold (E50) for the LT 8/4-ms waveform was 12.7 J compared to 43.5 J and 45.5 J for STB waveforms 6/6 ms and 8/4 ms, respectively, and 47.7 J for LT 12-ms waveform. The LT 8/4-ms waveform had no lasting detrimental effect on cardiac function, and any transient hemodynamical or biochemical changes observed were comparable to those observed with STB waveforms. %26lt;br%26gt;ConclusionLT waveforms are effective and appear safe in transvenous defibrillation in a porcine model of VF. The LT biphasic 8/4-ms waveform is more efficacious than conventional waveforms.

• 出版日期2014-3