Some recent randomized clinical trials in the management of atrial fibrillation

It is not possible to review all the recent randomized clinical trials in management of atrial fibrillation. The author has chosen to select a few that illustrate key points. "Immediate" or "early" recurrence of atrial fibrillation after electrical cardioversion is an important part of inefficacy of drug therapy and more insight into the mechanisms of this phenomenon is needed. Two recent trials in which verapamil, a calcium channel blocker, and irbesartan, an angiotensin receptor blocking agent, added to a standard antiarrhythmic attenuated early recurrences of atrial fibrillation are of particular interest. Trials of drugs and pacing for maintenance of sinus rhythm continue to demonstrate only modest efficacy. Amiodarone, the most effective agent, is not markedly better and there are concerns about its adverse effect profile during long-term use. Other nonpharmacologic therapies have not yet been, but will need to be, evaluated in properly designed randomized clinical trials with clinically important end-points. The absence of a simple, highly effective treatment for the maintenance of sinus rhythm with few adverse effects has been part of the foundation for recent trials comparing the rate control strategy to the rhythm control strategy, particularly in the elderly patient. Six such trials have been completed and one is in progress. The data from these trials is quite consistent for the elderly patient with stroke risk factors and predominantly persistent atrial fibrillation: (1) any advantage for the rhythm control strategy remains unproven; (2) the rate control strategy has some clear advantages and should be considered more often as a primary approach in such patients; and (3) anticoagulation should not be discontinued in such high risk patients, even when it is felt that sinus rhythm has been maintained. Anticoagulation is under-utilized in this setting and alternatives to warfarin are badly needed. Trials in progress may be helpful in this regard. Finally, primary prevention of atrial fibrillation needs more attention. Recent randomized trials with trandolapril after myocardial infarction and physiologic pacing have given some insight into how this might be accomplished.