Relapse and mortality following cardioversion of new-onset vs. recurrent atrial fibrillation and atrial flutter in the elderly.

AIMS: Trials of rate control vs. rhythm control for atrial fibrillation or flutter included few patients with new-onset arrhythmia. Our objective was to assess the relapse rate and the effect of the relapse of new-onset atrial arrhythmias on mortality after direct-current cardioversion (DCCV). METHODS AND RESULTS: A cohort of 351 patients with atrial fibrillation (new onset in 179) and 126 patients with atrial flutter (new onset in 78) was followed-up after DCCV. Cox proportional hazard models were used. Median age was 74.6 years. Mean follow-up for relapse was 7.7 months; for death, 29.4 months. Patients with new-onset atrial flutter [adjusted hazard ratio (HR) = 1] were more likely to maintain sinus rhythm than the patients with recurrent atrial flutter (adjusted HR = 2.5, P < 0.01), new-onset atrial fibrillation (adjusted HR = 2.4, P < 0.01), or recurrent atrial fibrillation (adjusted HR = 2.7, P < 0.01). Patients with new-onset atrial fibrillation were as likely to have relapses as patients with recurrent atrial fibrillation or flutter. Relapse of atrial arrhythmia after DCCV was associated with increased mortality (adjusted HR= 3.1, P < 0.01). CONCLUSION: DCCV is more successful in maintaining sinus rhythm in patients with new-onset atrial flutter than in patients with new-onset atrial fibrillation. Relapse of atrial arrhythmia after cardioversion is associated with increased mortality.

Safety of expedited anticoagulation in patients undergoing transesophageal echocardiographic-guided cardioversion.

BACKGROUND: In patients undergoing transesophageal echocardiography-guided cardioversion, we evaluated the use and safety of an expedited in-hospital anticoagulation regimen that incorporates shorter-than-standard durations of precardioversion intravenous unfractionated heparin and postcardioversion bridging therapy with a low-molecular-weight heparin. METHODS: Adult patients who underwent successful transesophageal echocardiography-guided cardioversion for atrial fibrillation or atrial flutter between May 2000 and August 2003 were classified into 2 groups by duration of intravenous unfractionated heparin therapy (<24 h or > or =24 h) before transesophageal echocardiography and cardioversion. Safety end points evaluated included all-cause death, stroke or other thromboembolic events, and major bleeding complications within 1 month after successful cardioversion. RESULTS: The study population of 386 patients included 199 (52%) who received expedited intravenous unfractionated heparin (<24 h; minimum duration, <4 h) and 193 patients (50%) who were discharged on low-molecular-weight heparin therapy. The adverse event rates at 1-month follow-up were not significantly different between the 2 unfractionated heparin patient groups, and the rate of stroke among patients dismissed on low-molecular-weight heparin was less than 1%. No adverse events occurred among patients who received intravenous unfractionated heparin for less than 12 hours and who were dismissed on low-molecular-weight heparin bridging therapy. CONCLUSIONS: The use of an expedited heparin anticoagulation regimen in patients with atrial fibrillation or atrial flutter undergoing transesophageal echocardiography-guided cardioversion appears to be safe. Cardioversion can be performed as early as a few hours after initiation of intravenous unfractionated heparin, and bridging therapy with a low-molecular-weight heparin can be used after cardioversion until the international normalized ratio is therapeutic.

Prospective, randomized comparison of two biphasic waveforms for the efficacy and safety of transthoracic biphasic cardioversion of atrial fibrillation.

OBJECTIVES: The purpose of this study was to determine if there is a difference in commercially available biphasic waveforms. BACKGROUND: Although the superiority of biphasic over monophasic waveforms for external cardioversion of atrial fibrillation (AF) is established, the relative efficacy of available biphasic waveforms is less clear. METHODS: We compared the effectiveness of a biphasic truncated exponential (BTE) waveform and a biphasic rectilinear (BR) waveform for external cardioversion of AF. Patients (N = 188) with AF were randomized to receive transthoracic BR shocks (50, 75, 100, 120, 150, 200 J) or BTE shocks (50, 70, 100, 125, 150, 200, 300, 360 J). Shock strength was escalated until success or maximum energy dose was achieved. If maximum shock strength failed, patients received the maximum shock of the opposite waveform. Analysis included 141 patients (71 BR, 70 BTE; mean age 66.5 +/- 13.7. Forty-seven randomized patients were excluded because of flutter on precardioversion ECG upon blinded review (n = 25), presence of intracardiac thrombus (n = 7), or protocol deviation (n = 15). Groups were similar with regard to clinical and echocardiographic characteristics. RESULTS: The success rate was similar for the two waveforms (93% BR vs 97 BTE, P = .44), although cumulative selected and delivered energy was less in the BTE group. Only AF duration was significantly different between successful and unsuccessful patients. No significant complications occurred. CONCLUSIONS: Biphasic waveforms were very effective in transthoracic cardioversion of AF, and complication rates were low. No significant difference in efficacy was observed between BR and BTE waveforms. Impedance was not an important determinant of success for either biphasic waveform.