Pharmacologic cardioversion for atrial fibrillation and flutter

Background. Atrial fibrillation is the most common cardiac dysrhythmia. It is associated with significant morbidity and mortality. There are two approaches to the management of atrial fibrillation: controlling the ventricular rate or converting to sinus rhythm in the expectation that this would abolish its adverse effects. Objectives. To assess the effects of pharmacologic cardioversion of atrial fibrillation in adults on the annual risk of stroke, peripheral embolism, and mortality. Search Strategy. The authors' searched the Cochrane Controlled Trials Register (issue 3, 2002), MEDLINE (2000 to 2002), EMBASE (1998 to 2002), CINAHL (1982 to 2002), and Web of Science (1981 to 2002). They hand searched the following journals (all 1997 to 2002): Circulation, Heart, European Heart Journal, and Journal of the American College of Cardiology, and selected abstracts published on the Web site of the North American Society of Pacing and Electrophysiology (2001, 2002). Selection Criteria. Randomized controlled trials or controlled clinical trials of pharmacologic cardioversion versus rate control in adults (older than 18 years) with acute, paroxysmal, or sustained atrial fibrillation or atrial flutter, of any duration and of any etiology. Data Collection and Analysis. One reviewer applied the inclusion criteria and extracted the data. Trial quality was assessed and the data were entered into RevMan. Primary Results. The authors identified two completed studies: AFFIRM(2) (n = 4,060) and PIAF(3) (n = 252). The authors found no difference in mortality between rhythm control and rate control (relative risk = 1.14; 95% confidence interval, 1.00 to 1.31). Both studies showed significantly higher rates of hospitalization and adverse events in the rhythm-control group and no difference in quality of life between the two treatment groups. In AFFIRM, there was a similar incidence of ischemic stroke, bleeding, and systemic embolism in the two groups. Certain malignant dysrhythmias were significantly more likely to occur in the rhythm-control group. There were similar scores of cognitive assessment. In PiAF, cardio-verted patients enjoyed an improved exercise tolerance, but there was no overall benefit in terms of symptom control or quality of life. Reviewers' Conclusions. The authors conclude that there is no evidence that pharmacologic cardioversion of atrial fibrillation to sinus rhythm is superior to rate control. Rhythm control is associated with more adverse effects and increased hospitalization, and it does not reduce the risk of stroke. This conclusion cannot be generalized to all persons with atrial fibrillation. Most of the patients included in these studies were older than 60 years and had significant cardiovascular risk factors.