Arrhythmic Burden and the Risk of Cardiovascular Outcomes in Patients With Paroxysmal Atrial Fibrillation and Cardiac Implanted Electronic Devices.

Background: Whether the amount of atrial fibrillation (AF) patients experience conveys important prognostic information beyond that provided by the diagnosis of AF is uncertain. The study objective was to assess the dose-response relationship between device-detected AF burden and subsequent cardiovascular outcomes.

Methods: Among patients with paroxysmal AF who underwent cardiac implantable electronic device implantation (2010-2016), Merlin.net remote-monitoring data were linked to Medicare claims to assess the magnitude and strength of the associations between device-based AF burden (defined as a daily percentage of time spent in AF or maximal AF episode duration ascertained at baseline over 30 days) and key cardiovascular outcomes.

Results: Among 39 710 patients (mean age 77.1±8.7 years, 60.7% male, and a mean CHADS-VASc score 4.9±1.3), all-cause mortality at 1-year increased with baseline AF burden: 8.54% with AF burden 0%, 8.9% with AF burden 0% to 5%, and 10.9% with AF burden 5% to 98% (<0.001) There was also a dose-response relationship between increasing AF burden and all-cause or cardiovascular hospitalization and ischemic stroke. Updating AF burden data every 30 days did not alter the AF burden-prognostic relationships determined from the use of baseline data alone. Results were also consistent when 3-year outcomes were considered and after accounting for the use of oral anticoagulants.

Conclusions: In paroxysmal AF, there is a clinically relevant dose-response relationship between increasing AF burden and rates of adverse outcomes at 1- and 3-years, including increasing risks of cardiovascular hospitalization, ischemic stroke, and mortality.