A comparison of 50-J versus 100-J shocks for direct-current cardioversion of atrial flutter.
BACKGROUND
Direct-current cardioversion remains the gold standard for restoration of sinus rhythm in patients with atrial flutter. Although an initial energy of 50 J is recommended, the optimal energy settings have not been evaluated in a large series of contemporary patients.


METHODS
We compared the outcome of cardioversion with 50 J versus 100 J in 330 consecutive patients with atrial flutter. Initial energy was based on attending physician preference. One hundred sixty patients received 50 J and 170 patients received 100 J.


RESULTS
Patients in both groups did not differ significantly in age, sex, weight, body mass index, duration of the arrhythmia, postoperative status, presence and type of structural heart disease, or use of antiarrhythmic drugs. Patients in the 100-J group had more first shock conversion (85% vs 70%; P =. 001), fewer total shocks (1.2 +/- 0.5 vs 1.4 +/- 0.7; P =.001), and less induction of atrial fibrillation (2% vs 11%; P =.002). There were no significant differences in overall restoration of sinus rhythm, cumulative energy delivered, anesthetic dose, and procedure room time. On multivariate analysis, delivery of 100 J was the strongest predictor of first shock success (odds ratio 2.6, 95% confidence interval 2.13 to 3.16; P <.001).


CONCLUSIONS
An initial energy of 100 J is more efficient for restoration of sinus rhythm in patients with atrial flutter.
Department of Cardiology, Cleveland Clinic Foundation, Cleveland, OH, USA. spinski@rush.edu
S L
SL
Pinski
E B
EB
Sgarbossa
E
E
Ching
R G
RG
Trohman
D000368:Aged; D000704:Analysis of Variance; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000209:etiology; D001282:Atrial Flutter / Q000628:therapy*; D015992:Body Mass Index; D002311:Cardiomyopathy, Dilated / Q000150:complications; D015331:Cohort Studies; D016001:Confidence Intervals; D003327:Coronary Disease / Q000150:complications; D004554:Electric Countershock / Q000009:adverse effects / Q000379:methods*; D004560:Electricity; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D008723:Methohexital / Q000008:administration & dosage; D008875:Middle Aged; D015999:Multivariate Analysis; D009200:Myocardial Contraction / Q000502:physiology; D016017:Odds Ratio; D013997:Time Factors; D016896:Treatment Outcome
D018686:Anesthetics, Intravenous; D000889:Anti-Arrhythmia Agents; D008723:Methohexital