Maximum-fixed energy shocks for cardioverting atrial fibrillation.
AIMS
Direct-current cardioversion is one of the most commonly performed procedures in cardiology. Low-escalating energy shocks are common practice but the optimal energy selection is unknown. We compared maximum-fixed and low-escalating energy shocks for cardioverting atrial fibrillation.


METHODS AND RESULTS
In a single-centre, single-blinded, randomized trial, we allocated elective atrial fibrillation patients to cardioversion using maximum-fixed (360-360-360 J) or low-escalating (125-150-200 J) biphasic truncated exponential shocks. The primary endpoint was sinus rhythm 1 min after cardioversion. Safety endpoints were any arrhythmia, myocardial injury, skin burns, and patient-reported pain after cardioversion. We randomized 276 patients, and baseline characteristics were well-balanced between groups (mean ± standard deviation age: 68 ± 9 years, male: 72%, atrial fibrillation duration >1 year: 30%). Sinus rhythm 1 min after cardioversion was achieved in 114 of 129 patients (88%) in the maximum-fixed energy group, and in 97 of 147 patients (66%) in the low-escalating energy group (between-group difference; 22 percentage points, 95% confidence interval 13-32, P < 0.001). Sinus rhythm after first shock occurred in 97 of 129 patients (75%) in the maximum-fixed energy group compared to 50 of 147 patients (34%) in the low-escalating energy group (between-group difference; 41 percentage points, 95% confidence interval 30-51). There was no significant difference between groups in any safety endpoint.


CONCLUSION
Maximum-fixed energy shocks were more effective compared with low-escalating energy shocks for cardioverting atrial fibrillation. We found no difference in any safety endpoint.
['Schmidt|Anders S|AS|', 'Lauridsen|Kasper G|KG|', 'Torp|Peter|P|', 'Bach|Leif F|LF|', 'Rickers|Hans|H|', 'Løfgren|Bo|B|']
D000368:Aged D001281:Atrial Fibrillation D004554:Electric Countershock D005260:Female D006335:Heart Injuries D006801:Humans D008297:Male D008875:Middle Aged D011446:Prospective Studies D016896:Treatment Outcome
Atrial fibrillation Cardioversion Energy selection