Detection of Atrial Fibrillation After Surgical Ablation: Conventional Versus Continuous Monitoring

Background: Current guidelines recommend at least 24-hour Holter monitoring at 6-month intervals to evaluate the recurrence of atrial fibrillation (AF) after surgical ablation. In this prospective multicenter study, conventional intermittent methods of AF monitoring were compared with continuous monitoring using an implantable loop recorder (ILR).

Methods: From August 2011 to January 2014, 47 patients receiving surgical treatment for AF at 2 institutions had an ILR placed at the time of operation. Each atrial tachyarrhythmia (ATA) of 2 minutes or more was saved. Patients transmitted ILR recordings bimonthly or after any symptomatic event. Up to 27 minutes of data was stored before files were overwritten. Patients also underwent electrocardiography (ECG) and 24-hour Holter monitoring at 3, 6, and 12 months. ILR compliance was defined as any transmission between 0 and 3 months, 3 and 6 months, or 6 and 12 months. Freedom from ATAs was calculated and compared.

Results: ILR compliance at 12 months was 93% compared with ECG and Holter monitoring compliance of 85% and 76%, respectively. ILR devices reported a total of 20,878 ATAs. Of these, 11% of episodes were available for review and 46% were confirmed as AF. Freedom from ATAs was no different between continuous and intermittent monitoring at 1 year. Symptomatic events accounted for 187 episodes; however, only 10% were confirmed as AF.

Conclusions: ILR was equivalent at detecting ATAs when compared with Holter monitoring or ECG. However, the high rate of false-positive readings and the limited number of events available for review present barriers to broad implementation of this form of monitoring. Very few symptomatic events were AF on review.