Initial clinical experience with ambulatory use of an implantable atrial defibrillator for conversion of atrial fibrillation

Background-A recent study has shown that the implantable atrial defibrillat or can restore sinus rhythm in patients with recurrent atrial fibrillation when therapy was delivered under physician observation. The objective of th is study was to evaluate the safety and efficacy of ambulatory use of the i mplantable atrial defibrillator, Methods and Results-An atrial defibrillator was implanted in 105 patients ( 75 men; mean age, 59+/-12 years) with recurrent, symptomatic, drug-refracto ry atrial fibrillation, After successful 3-month testing, patients could tr ansition to ambulatory delivery of shock therapy. Patients completed questi onnaires regarding shock therapy discomfort and therapy satisfaction using a 10-point visual-analog scale (1 represented "not at all," 10 represented "extremely") after each treated episode of atrial fibrillation, During a me an follow-up of 11.7 months, 48 of 105 patients satisfied criteria for tran sition and received therapy for 275 episodes of atrial fibrillation, Overal l shock therapy efficacy was 90% with 1.6+/-1.2 shocks delivered per episod e (median, 1). Patients rated shock discomfort as 5.2+/-2.4 for successful therapy and 4.2+/-2.2 for unsuccessful therapy (P>0.05), The satisfaction s core was higher for successful versus unsuccessful therapy (3.4+/-3.3 versu s 8.7+/-1.3, P<0.05). There was no ventricular proarrhythmia observed throu ghout the course of this study. Conclusions-Ambulatory use of an implantable atrial defibrillator can safel y and successfully convert most episodes of atrial fibrillation, often requ iring only a single shock. Successful therapy is associated with high satis faction and only moderate discomfort.