CRT device interrogation reveals under-recognition of atrial fibrillation within a heart failure cohort

Patients with heart failure develop atrial fibrillation (AF) more frequently than the generalpopulation, with many heart failure studies reporting AF prevalences ranging from 20 to50%. These studies diagnosed AF via standard ECG. Such diagnostic strategies fail to detectasymptomatic episodes of AF that often occur during AF development. In patients with heartfailure, the development of AF has been associated with increased risk of stroke, all-causemortality and hospitalization, and hence the importance of identifying these at risk patients.Retrospectively, we examined the cardiac resynchronization therapy (CRT) device records of162 heart failure patients to determine the prevalence of permanent, persistent, and paroxysmalAF as per current ESC criteria. AF episodes were defined as a period of mode-switchingon the CRT devices with atrial rate .200 for over 30 s. Medical records were reviewed toestablish each patient???s perceived AF status. Within our cohort of 162 patients, 49 had permanent/persistent AF (30.2%), 12 paroxysmal AF (7.4%), and 101 (62.3%) were not knownto have a previous history of AF. Of the 101 patients thought to be persistently in sinusrhythm, 27 had asymptomatic episodes of AF (26.7%) detected by their device (Figure 1A).All of these patients had paroxysmal AF rather than persistent AF. The mean AF burdenwithin this ???new??? paroxysmal AF group was 1.6 + 0.9%, and the longest episode durationwas 5.6 + 2.3 h (Figure 1B). This was substantially less than the mean AF burden(20.7 + 9.4%, P , 0.05) and longest episode duration (35.9 + 10.1 h, P , 0.01) inpatients who were known to have paroxysmal AF. Anticoagulation rates within the ???new??? paroxysmalAF group were significantly lower than the known paroxysmal AF group (66.6 vs.13.5%, respectively, P , 0.01). A significant number of heart failure patients perceived tobe persistently in sinus rhythm have undiagnosed, asymptomatic episodes of AF. Thesepatients are rarely anticoagulated. Further studies are warranted to assess the clinical sequelaeof such low AF burdens and the need for formal anticoagulation in these potentially ???at risk???heart failure patients.