Asymptomatic episodes of device-registered atrial tachyarrhythmia are not associated with worse cardiac resynchronization therapy response.

Aims: To assess the influence of device-registered episodes of atrial tachyarrhythmia (AT) on the response to cardiac resynchronization therapy (CRT).

Methods And Results: Consecutive CRT patients without history of atrial fibrillation (AF; n = 118) were followed prospectively. AT was defined as a device-registered episode of atrial rate >190 b.p.m. for ≥30 s. Episodes of electrocardiographically documented AF, accompanied by symptoms, or need for cardioversion, were classified as clinical AF. During mean follow-up of 26 ± 9 months, 39 patients (33%) had ≥1 episode of asymptomatic device-registered AT. Twenty-one patients (18%) developed clinical AF of whom seven had previously experienced episodes of asymptomatic device-registered AT. Patients with asymptomatic AT or AF had a higher body mass index, but otherwise similar baseline characteristics, compared with the subjects without AT. Reverse remodelling after CRT was similar among the groups. While clinical AF was significantly associated with the composite endpoint of all-cause mortality or unplanned hospital admission (hazard ratio = 2.43, 95% confidence interval: 1.40-4.24), this correlation was not observed in patients with asymptomatic device-registered AT (P value = 0.540).

Conclusion: Episodes of asymptomatic device-registered AT are frequent in CRT patients, but are not associated with impaired reverse remodelling. In contrast to clinical AF, such episodes are not associated with worse clinical outcome.