Intermittent rhythm monitoring for the detection of atrial fibrillation after ablation interventions: Gambling or science?

Objectives: Intermittent rhythm monitoring (IRM) is the most frequently used modality employed for the detection atrial fibrillation (AF) recurrence after therapeutic interventions. The data obtained from IRM are then used to draw inferences on the success or failure of surgical or interventional therapies for atrial fibrillation. We sought to investigate the sensitivity of various IRM strategies using a novel probabilistic approach on a continuous monitored patient population with proven AF recurrence.

Methods: Rhythm histories of 473 patients (mean AF burden, 0.16 ± 0.24, 491 patient*years follow-up, mean follow-up: 1.03 ± 0.33 years) with implantable CM devices (Reveal XT 9529 or AT500 pacemaker; Medtronic, Inc, Minneapolis, MN) and proven AF recurrence were reconstructed and analyzed. With the use of computationally intensive simulation, virtual IRMs were performed and the success rate and sensitivity of IRM of various frequencies and durations on the identification of AF recurrence was evaluated.

Results: Prolonged-duration IRM (7-, 14-, 30- days monitoring) was superior to shorter IRM (24h monitoring) (P< 0.0001). However, even with aggressive IRM strategies, AF recurrence was not detected in a great proportion of patients. The most often used IRM strategy (4 24h Holter per year) failed to identify AF recurrence in almost 50% of patients with proven AF recurrence thus offering no better insight for AF recurrence detection in these patients than the tossing of a fair coin.

Conclusions: IRM follow-up is unreliable and significantly inferior to CM. IRM strategies will not identify AF recurrence in a great proportion of patients at risk. When relying on IRM for rhythm monitoring to identify AF recurrence, chance has an immerse and immeasurable effect on the outcomes. For the scientific, evidence-based evaluation of AF treatments, CM should be strongly recommended.