Comparison of a novel rectilinear biphasic waveform with a damped sine wave monophasic waveform for transthoracic ventricular defibrillation

Mittal, Suneet; Ayati, Shervin; Steín, Kenneth M.; Knight, Bradley P.; Morady, Fred; Schwartzman, David; Cavlovich, Doris; Platia, Edward V.; Calkins, Hugh; Tchou, Patrick; Miller, John M.; Wharton, J. Marcus; Sung, Ruey J.; Slotwiner, David J.; Markowitz, Steven M.; Lerman, Bruce B.

doi:10.1016/s0735-1097(99)00363-0

Cited by 103 publications

(36 citation statements)

References 27 publications

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“…These studies, performed primarily to support US Food and Drug Administration clearance of new biphasic waveforms, documented that a variety of biphasic shock doses can terminate VF at least as effectively as conventional monophasic shocks of 200 J. [21][22][23][24] More recent studies have described the performance of specific biphasic energy doses during attempted resuscitation from in-hospital and out-of-hospital cardiac arrest. High VF termination rates have generally been reported for initial 150- to 200-J biphasic shocks delivered from first-responder AEDs.…”

Section: Stiell Et Al Randomized Trial Of Biphasic Defibrillation Energymentioning

confidence: 99%

BIPHASIC Trial

et al. 2007

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Background-There is little clear evidence as to the optimal energy levels for initial and subsequent shocks in biphasic waveform defibrillation. The present study compared fixed lower-and escalating higher-energy regimens for out-of-hospital cardiac arrest. Methods and Results-The Randomized Controlled Trial to Compare Fixed Versus Escalating Energy Regimens forBiphasic Waveform Defibrillation (BIPHASIC Trial) was a multicenter, randomized controlled trial of 221 out-ofhospital cardiac arrest patients who received Ն1 shock given by biphasic automated external defibrillator devices that were randomly programmed to provide, blindly, fixed lower-energy (150-150-150 J) or escalating higher-energy (200-300-360 J) regimens. Patient mean age was 66.0 years; 79.6% were male. The cardiac arrest was witnessed in 63.8%; a bystander performed cardiopulmonary resuscitation in 23.5%; and initial rhythm was ventricular fibrillation/ ventricular tachycardia in 92.3%. The fixed lower-and escalating higher-energy regimen cases were similar for the 106 multishock patients and for all 221 patients. In the primary analysis in multishock patients, conversion rates differed significantly (fixed lower, 24.7%, versus escalating higher, 36.6%; Pϭ0.035; absolute difference, 11.9%; 95% CI, 1.2 to 24.4). Ventricular fibrillation termination rates also were significantly different between groups (71.2% versus 82.5%; Pϭ0.027; absolute difference, 11.3%; 95% CI, 1.6 to 20.9). For the secondary analysis of first shock success, conversion rates were similar between the fixed lower and escalating higher study groups (38.4% versus 36.7%; Pϭ0.92), as were ventricular fibrillation termination rates (86.8% versus 88.8%; Pϭ0.81). There were no distinguishable differences between regimens for survival outcomes or adverse effects. Conclusions-This is the first randomized trial to compare fixed lower and escalating higher biphasic energy regimens in out-of-hospital cardiac arrest, and it demonstrated higher rates of ventricular fibrillation conversion and termination with an escalating higher-energy regimen for patients requiring multiple shocks. These results suggest that patients in ventricular fibrillation benefit from higher biphasic energy levels if multiple defibrillation shocks are required.

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Section: Stiell Et Al Randomized Trial Of Biphasic Defibrillation Energymentioning

confidence: 99%

BIPHASIC Trial

et al. 2007

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“…As the field of clinical defibrillation matured, numerous studies were devoted to find the optimal shock waveform that would accomplish defibrillation with minimal delivered energy. It was shown that morphologically distinct waveforms have different defibrillation efficacies in both experimental studies (18,19,26,32,42) and theoretical studies using lumped models (16,43). However, the experimental studies that elucidate mechanisms for differences in defibrillation efficacies of the various waveforms are lacking.…”

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confidence: 99%

Mechanisms of superiority of ascending ramp waveforms: new insights into mechanisms of shock-induced vulnerability and defibrillation

Li²,

Nikolski

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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. Mechanisms of superiority of ascending ramp waveforms: new insights into mechanisms of shock-induced vulnerability and defibrillation. Am J Physiol Heart Circ Physiol 289: H569 -H577, 2005. First published March 25, 2005; doi:10.1152/ajpheart.01117.2004.-Monophasic ascending ramp (AR) and descending ramp (DR) waveforms are known to have significantly different defibrillation thresholds. We hypothesized that this difference arises due to differences in mechanisms of arrhythmia induction for the two waveforms. Rabbit hearts (n ϭ 10) were Langendorff perfused, and AR and DR waveforms (7, 20, and 40 ms) were randomly delivered from two line electrodes placed 10 mm apart on the anterior ventricular epicardium. We optically mapped cellular responses to shocks of various strengths (5, 10, and 20 V/cm) and coupling intervals (CIs; 120, 180, and 300 ms). Optical mapping revealed that maximum virtual electrode polarization (VEP) was reached at significantly different times for AR and DR of the same duration (P Ͻ 0.05) for all tested CIs. As a result, VEP for AR were stronger than for DR at the end of the shock. Postshock break excitation resulting from AR generated faster propagation and typically could not form reentry. In contrast, partially dissipated VEP resulting from DR generated slower propagation; the wavefront was able to propagate into deexcited tissue and thus formed a shock-induced reentry circuit. Therefore, for the same delivered energy, AR was less proarrhythmic compared with DR. An active bidomain model was used to confirm the electrophysiological results. The VEP hypothesis explains differences in vulnerability associated with monophasic AR and DR waveforms and, by extension, the superior defibrillation efficacy of the AR waveform compared with the DR waveform.

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“…29 This delay is difficult to justify in light of the first-shock efficacy of Ͼ90% reported by current biphasic defibrillators. 28,[35][36][37][38][39] AED manufacturers should seek innovative methods to decrease the amount of time chest compressions are interrupted for AED operation. Training materials for lay rescuers should emphasize the importance of continued CPR until basic or advanced life support personnel take over CPR or the victim begins to move.…”

Section: -Shock Protocol Versus 3-shock Sequencementioning

confidence: 99%