Epicardial, biatrial synchronous pacing for prevention of atrial fibrillation after cardiac surgery

About 30% of patients develop AF after open heart surgery. Biatrial synchro nous pacing (BSP) has been shown to promote sinus rhythm in patients with p aroxysmal AF refractory to drug therapy. We conducted a prospective, random ized study to test the effect of BSP via epicardial electrodes on the incid ence of AF after heart surgery, as compared to conventional therapy. To app ly BSP, we attached two epicardial electrodes to the right and one to the l eft atrium. Immediately following surgery, BSP was initiated in the AAI-Mod e at a rate of 10 beats/min above the underlying rhythm (maximum 110 beats/ min) and continued for 3 days, during which the rhythm was continually moni tored. After 21 (age 63 +/- 9 years) of the planned 200 patients, the study was prematurely aborted because of the proarrhythmic effect of BSP: 6 of t he 12 patients treated with BSP developed sensing failure IP amplitude < 1 mV), which provoked AF in 5 of these 6 patients. BSP was discontinued due t o diaphragmal stimulation in two patients and due to ventricular stimulatio n by a dislocated left atrial electrode in one patient. Two patients in the control group (n = 9) developed AF. Using the available standard technolog y, BSP via epicardial electrodes is not suitable to suppress AF after heart surgery, primarily due to postoperative deterioration of atrial sensing an d its profibrillatory effect. In patients requiring atrial pacing after hea rt surgery, sensing thresholds must be closely monitored to prevent inducti on of AF.