Overdrive atrial pacing for conversion of atrial flutter: Comparison of postoperative with nonpostoperative patients

Background Previous studies have reported varying success rates in overdriv e pace termination of atrial Flutter. We hypothesized that these discrepanc ies might be caused by differences in study populations. Accordingly, we pr ospectively compared the success rate of pacing in patients with atrial flu tter that occurred after heart surgery with that of patients with atrial fl utter from other causes. Methods and Results The study population consisted of 65 consecutive patien ts referred for pace termination of typical (type I) atrial flutter. Pacing was performed in 30-second bursts, starting at the flutter cycle length, a nd repeated in 5-ms decrements until normal sinus rhythm or atrial fibrilla tion occurred. Normal sinus rhythm was restored in 38 (65%) patients. Of 20 patients whose flutter was precipitated by heart surgery, 19 (95%) were su ccessfully pace terminated. In contrast, pace termination was successful in only 47% of the remainder of the population (P < .001). No other clinical parameters were predictive of outcome. Conclusions We conclude that overdrive pacing is an effective means of term inating atrial flutter that has occurred after heart surgery. Alternative m ethods should be considered as the initial therapeutic approach in patients with atrial flutter from other causes.