Spontaneous episodes of atrial fibrillation after implantation of the Metrix Atrioverter: Observations on treated and nontreated episodes

OBJECTIVES We sought to evaluate the number and duration of device-treated and self-terminating, nontreated episodes of atrial fibrillation (AF) after implantation of the Metrix Atrioverter. BACKGROUND A recent study has shown that the Atrioverter can rapidly restor e sinus rhythm in patients with AF; however, the effect of the device on th e clinical course of the arrhythmia in these patients is unknown. METHODS The Atrioverter was implanted in 51 patients with symptomatic, recu rrent, drug-refractory AF. The device was programmed to periodically monito r the cardiac rhythm. Defibrillation of AF episodes was performed under phy sician observation. RESULTS During a mean follow-up of 260 +/- 144 days, 1,161 episodes of AF w ere observed during valid monitoring periods in 45 of 51 patients. Forty-on e patients experienced 231 episodes for which they sought defibrillation th erapy. The average duration of the treated episodes during valid monitoring periods (190 of 231 episodes in 39 of 41 patients) was significantly longe r than that of the nontreated episodes (38 +/- 44 vs. 10 +/- 8 h; p < 0.05) . The time between episodes requiring Atrioverter therapy increased, and th e risk of having an episode requiring treatment decreased. No changes were observed in the number and duration of the short-lasting, nontreated episod es as time since implantation of the device increased. CONCLUSIONS In patients with symptomatic, recurrent, drug-refractory AF, th e frequency of long-lasting episodes, which were treated under observation with repeated defibrillation using the Atrioverter, decreased. The number a nd duration of short-lasting, nontreated episodes did not change during the 20-month study period. The effect of ambulatory use of the device on the r ecurrence of short-lasting episodes needs to be evaluated. (C) 2000 by the American College of Cardiology.