Prediction of uneventful cardioversion and maintenance of sinus rhythm from direct-current electrical cardioversion of chronic atrial fibrillation and flutter.

The present study was undertaken to reassess prospectively the immediate and long-term results of direct-current electrical cardioversion in chronic atrial fibrillation or atrial flutter, and to determine factors predicting clinical outcome of the arrhythmia after direct-current cardioversion. Two-hundred forty-six patients underwent direct-current electrical cardioversion and were followed during a mean of 260 days. Multivariate analysis was used to identify factors predicting short- and long-term arrhythmia outcome. Cardioversion was achieved in 70% of patients with atrial fibrillation and in 96% of patients with atrial flutter. Stepwise logistic regression analysis revealed that arrhythmia duration (p less than 0.001), type of arrhythmia (fibrillation vs flutter, p less than 0.02) and age (p less than 0.05) independently influenced conversion rate. On an actuarial basis, 42 and 36% of patients remained in sinus rhythm during 1 and 2 years, respectively. Multivariate regression analysis revealed that the type of arrhythmia (p = 0.0008), low precardioversion functional class (p = 0.002) and the presence of nonrheumatic mitral valve disease (p = 0.03) independently increased the length of the arrhythmia-free episode. Rheumatic heart disease shortened this period (p = 0.03). In conclusion, patients having a high probability of conversion together with a prolonged post-shock arrhythmia-free episode can be identified. This may improve the cost-benefit ratio of cardioversion.