Effects of circumferential or segmental pulmonary vein ablation for paroxysmal atrial fibrillation on cardiac autonomic function

BACKGROUND Circumferential and segmental pulmonary vein ablations are two established treatment strategies for ablation of atrial fibrillation. Both techniques require the application of radiofrequency current at anatomical sites that are close to autonomic ganglia. However, the effects of current pulmonary vein ablation techniques on cardiac autonomic function are unknown. OBJECTIVE The purpose of this study was to analyze the short- and long-term effects of circumferential and segmental pulmonary vein ablation on cardiac autonomic function. METHODS One hundred patients with highly symptomatic atrial fibrillation were randomly assigned to undergo either circumferential or segmental pulmonary vein ablation. Hotter recordings were recorded at baseline and at regular intervals for up to 1 year after ablation. Autonomic function was assessed by deceleration capacity and acceleration capacity of heart rate as well as by standard measures of heart rate variability. RESULTS In the circumferential pulmonary vein ablation group, deceleration capacity and acceleration capacity decreased highly significantly from 5.7 +/- 2.1 ms and -8.0 +/- 1.9 ms at baseline to 3.3 +/- 1.8 ms and -5.5 +/- 2.3 ms directly after ablation, respectively (P<.00001). Impairment of deceleration capacity and acceleration capacity was present up to 1 year after ablation. In the segmental pulmonary vein ablation group, deceleration capacity and acceleration capacity decreased from 5.8 +/- 2.0 ms and -7.8 +/- 1.6 ms at baseline to 3.4 +/- 1.2 ms and -6.0 +/- 2.4 ms directly after ablation (P<.00001), respectively. However, deceleration capacity and acceleration capacity returned to baseline values within 1 month. CONCLUSIONS Circumferential and segmental pulmonary vein ablations induce an immediate decrease of autonomic function. However, while this decrease is only transient with segmental pulmonary vein ablation, it persists with circumferential pulmonary vein ablation for at least 1 year.