Introduction: Surgical atrial fibrillation (AF) therapy is gaining widespread acceptance among cardiothoracic surgeons. However, assessment of therapy success is until now solely based on short time -“snapshot”-rhythm surveillance often at irregular time intervals. In order to evaluate the ablation’s success we intraindividually compared two different types of follow-up strategies: conventional 24h-Holter monitoring and direct long time rhythm surveillance achieved by a new implantable monitor device (IRMD).
Methods: 20 cardiac surgical patients (male 16, mean age 69±9y) with a mean AF of 30±48m (paroxysmal n=7, persistent n=9, long standing persistent n=4) were treated intraoperatively with epicardial high intensity focus ultrasound (HIFU) ablation (+CABG n=10, +AVR n=5, +AVR/CABG n=2, +valve preserving ascending aorta replacement n=2, +endoaneurymoraphy n=1, lone atrial fibrillation n=1). Postoperative heart rhythm monitoring was accomplished in all patients with a 24h-Holter-monitor at prescheduled time intervals and additionally with a new implantable monitor device (Reveal XT, Medtronic®, MN, USA). A more than 0.5% of “time in AF” as reported by the IRMD was considered as recurrence of AF. Telemetry of the IRMD was performed simultaneously after completion of 24h-Holter monitoring.
Results: During a mean FU of 8.7±1.4m a total of 29 24 h-Holter-monitors were obtained. Sinus rhythm was documented in 21, the IMRD however revealed AF recurrence in 11 of these cases. Thus, conventional 24 h ECG monitoring failed to identify AF recurrence in 59% of cases (p<0.027). Success rate after surgical ablation therapy (defined as freedom from AF recurrence of more than 0.5% of observational period) was 72% with 24h Holter monitoring, but only 35% using continuous ECG monitoring with IRMD.
Conclusion: In order to evaluate better “real life” outcomes after atrial fibrillation ablation therapy, long term continuous heart rhythm surveillance instead of -“snapshot” - heart rhythm monitoring is mandatory. This is particularly important for the decision to alter medical therapies, e.g. oral anticoagulation or antiarrhythmic treatment.