Botto GL, Politi A, Bonini W, et al. External cardioversion of atrial fibrillation: role of paddle position on technical efficacy and energy requirements. Heart. 1999;82:726–730. | Randomized controlled trial comparing elective DCCV using AL paddle position vs AP paddle position in patients with stable AF | 301 patients enrolled; higher success rate of conversion to NSR in AP group (87%) vs AL group (76%) (p = 0.013); arrhythmia duration was the only factor that affected the technical success of DCCV | Exclusion criteria included patients with AF duration > 2 years or of unknown duration; technical success was defined as interruption of AF for > 10 seconds; pharmacological antiarrhythmic treatment was not randomized | An AP paddle position is superior to an AL location with regard to success in DCCV of stable AF and permits lower shock energy requirements |
Klein AL, Grimm RA, Murray RD, et al. Assessment of Cardioversion Using Transesophageal Echocardiography Investigators. Use of transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation. N Engl J Med. 2001;344: 1411–1420. | Multicenter, randomized controlled trial comparing TEE-guided vs conventional treatment (warfarin for 3 weeks) in patients with AF > 48 hours undergoing elective DCCV | 1222 patients enrolled; there was no significant difference between the TEE-guided group (0.8%) vs conventional treatment group (0.5%) (p = 0.50) in the rate of embolic events; fewer hemorrhagic events in TEE-guided group (2.9%) vs conventional treatment (5.5%) (p = 0.03) | Short duration of follow-up (8 weeks); there was greater use of antiarrhythmic medication in the conventional treatment group at the time of cardioversion (92.8%) vs TEE-guided group (82.2%) (P < 0.001) | TEE-guided cardioversion allows for early, safe cardioversion of AF and may be considered a clinically effective alternative to conventional therapy |
Niebauer MJ, Brewer JE, Chung MK, et al. Comparison of the rectilinear biphasic waveform with the monophasic damped sine waveform for external cardioversion of atrial fibrillation and flutter. Am J Cardiol. 2004;93:1495–1499. | Retrospective trial comparing the results of DCCV using biphasic waveform to monophasic waveform in patients with AF and AFL | 1361 patients in biphasic waveform group; 2025 patients in monophasic waveform group; overall success rate for AF was 99.8% in biphasic group and 92.4% in monophasic group (P < 0.001); successful energy for cardioversion of AF in biphasic group (median = 100 j) compared to monophasic group (median = 200 j) | Methodological limitations inherent to retrospective study design | Very high success rate for cardioversion of AF/AFL with biphasic waveform; monophasic waveform equally effective for AFL but significantly less effective in terminating AF; biphasic waveform permits lower shock energy requirements |
Oral H, Souza JJ, Michaud GF, et al. Facilitating transthoracic cardioversion of atrial fibrillation with ibutilide pretreatment. N Engl J Med. 1999; 340:1849–1854. | Randomized controlled trial comparing DCCV with and without pretreatment with 1 mg of ibutilide in patients with AF | 100 patients enrolled; conversion to NSR (100%) with ibutilide pretreatment; conversion to NSR (72%) without pretreatment (p < 0.001); all patients in whom DCCV alone failed, NSR was restored when cardioversion was attempted again after the administration of ibutilide | Only one technique for DCCV was used; many patients were currently being treated with antiarrhythmic drugs, and a synergistic effect with ibutilide could not be ruled out | Efficacy of DCCV for converting AF to NSR was enhanced by pretreatment with ibutilide; pretreatment with ibutilide was associated with lower shock energy requirements |
Stambler BS, Wood MA, Ellenbogen KA, et al. Efficacy and safety of repeated intravenous doses of ibutilide for rapid conversion of atrial flutter or fibrillation. Ibutilide Repeat Dose Study Investigators. Circulation. 1996;94: 1613–1621. | Randomized controlled trial comparing intravenous ibutilide to placebo for pharmacologic cardioverson of AF or AFL | 261 patients enrolled; conversion rate with ibutilide (47%) vs placebo (2%) (P < 0.0001); efficacy higher in AFL (63%) vs AF (31%) (P < 0.0001); arrhythmia termination occurred a mean of 27 minutes after start of ibutilide infusion; 8.3% patients developed polymorphic VT with ibutilide | Methodological limitations inherent to placebo-controlled design; only patients with sustained AF/AFL > 3 hours and < 45 days were enrolled | Intravenous ibutilide given in repeated doses (under monitored conditions) is effective in rapidly terminating AF and AFL and is an alternative to current cardioversion options |