• sinus node;
  • atrial flutter;
  • electrical remodeling;
  • pacemaker

Sinus Node Remodeling.Introduction: The purpose of this study was to investigate the effect of ablation of right atrial flutter upon sinus node function in humans.

Methods and Results:This study enrolled 35 patients. Twenty-four patients (16 men and 8 women; age 68 ± 11 years) were referred for ablation of persistent atrial flutter (duration 8 ± 11 months). After ablation, there was abnormal sinus node function defined as a corrected sinus node recovery time (CSNRT) > 550 msec. The control group consisted of 11 patients who were undergoing pacemaker implantation for sinus node disease but did not have a history of atrial dysrhythmias or ablation. Within 24 hours of ablation or pacemaker implantation, baseline maximal CSNRT was measured through a permanent pacemaker by AAI pacing at six cycle lengths: 600, 550, 500, 450, 400, and 350 msec. CSNRT then was measured in the same manner at 48 hours, 14 days, and 3 months after ablation/pacemaker implantation. P wave amplitude and duration, and percent atrial sensing also were assessed at the same intervals. For patients undergoing atrial flutter ablation, there was progressive temporal recovery of CSNRT (1,204 ± 671 msec at baseline vs 834 ± 380 msec at 3 months; P < 0.001) and a significant increase in the percent atrial sensing and P wave amplitude at 3 months compared with baseline (P < 0.001). In control subjects, there was no change in the CSNRT, percent atrial pacing, or P wave amplitude.

Conclusion: After ablation of persistent atrial flutter, there is temporal recovery of CSNRT and increase in spontaneous atrial activity. These findings suggest that atrial flutter induces reversible changes in sinus node function.