Autonomic Alterations After Pulmonary Vein Isolation in the CIRCA-DOSE (Cryoballoon vs Irrigated Radiofrequency Catheter Ablation) Study

Abstract

Background The natural history of autonomic alterations following catheter ablation of drug-refractory paroxysmal atrial fibrillation is poorly defined, largely because of the historical reliance on non-invasive intermittent rhythm monitoring for outcome ascertainment. Methods and Results The study included 346 patients with drug-refractory paroxysmal atrial fibrillation undergoing pulmonary vein isolation using contemporary advanced-generation ablation technologies. All patients underwent insertion of a Reveal LINQ (Medtronic) implantable cardiac monitor before ablation. The implantable cardiac monitor continuously recorded physical activity, heart rate variability (measured as the SD of the average normal-to-normal), daytime heart rate, and nighttime heart rate. Longitudinal autonomic data in the 2-month period leading up to the date of ablation were compared with the period from 91 to 365 days following ablation. Following ablation there was a significant decrease in SD of the average normal-to-normal (mean difference versus baseline of 19.3 ms; range, 12.9-25.7; P<0.0001), and significant increases in daytime and nighttime heart rates (mean difference versus baseline of 9.6 bpm; range, 7.4-11.8; P<0.0001, and 7.4 bpm; range, 5.4-9.3; P<0.0001, respectively). Patients free of arrhythmia recurrence had significantly faster daytime (11±11 versus 8±12 bpm, P=0.001) and nighttime heart rates (8±9 versus 6±8 bpm, P=0.049), but no difference in SD of the average normal-to-normal (P=0.09) compared with those with atrial fibrillation recurrence. Ablation technology and cryoablation duration did not influence these autonomic nervous system effects. Conclusions Pulmonary vein isolation results in significant sustained changes in the heart rate parameters related to autonomic function. These changes are correlated with procedural outcome and are independent of the ablation technology used. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01913522.

Keywords: atrial fibrillation; atrial fibrillation arrhythmia; autonomic; autonomic function; autonomic nervous system.

Conflict of interest statement

Dr Andrade reports grants and personal fees from Medtronic, grants from Baylis, and personal fees from Biosense‐Webster; Dr Verma reports grants and personal fees from Medtronic and Biosense‐Webster; Dr Deyell reports grants from Biosense‐Webster; Dr Macle reports personal fees from Medtronic, grants and personal fees from St. Jude Medical/Abbott and Biosense‐Webster. The remaining authors have no disclosures to report.

Figures

Figure 1. Autonomic alterations pre‐ and post‐pulmonary vein isolation in the study cohort.

Pictured are median and interquartile ranges of the daytime heart rate (A), nighttime heart rate (B), and the SD of the average normal‐to‐normal intervals (C). Date of ablation is noted as time zero on the y‐axis, with a range of −91 days before ablation, and +366 days post‐ablation. SDANN indicates SD of the average normal‐to‐normal intervals.

Figure 2. Autonomic alterations pre‐ and post‐pulmonary vein isolation, stratified by randomized group.

Pictured are median values of the daytime heart rate (A), nighttime heart rate (B), and the SD of the average normal‐to‐normal intervals (C). Date of ablation is noted as time zero on the Y axis, with a range of −91 days before ablation, and +366 days post‐ablation. Black line depicts patients randomized to contact‐force radiofrequency ablation, red line depicts those randomized to short duration cryoablation, and pink line depicts those randomized to standard duration cryoablation. CRYO indicates cryoballoon ablation; SDANN, SD of the average normal‐to‐ normal.

Figure 3. Autonomic alterations pre‐ and post‐pulmonary vein isolation, stratified by procedural outcome.

Pictured are median values of the daytime heart rate (A), nighttime heart rate (B), and the SD of the average normal‐to‐normal intervals (C). Date of ablation is noted as time zero on the y‐axis, with a range of −100 days before ablation, and +365 days post‐ablation. Red line depicts patients with recurrence of atrial fibrillation/atrial flutter/atrial tachycardia, and green line depicts patients free of arrhythmia recurrence.