High Incidence of De Novo and Subclinical Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy and Cardiac Rhythm Management Device.

Introduction: Atrial fibrillation (AF) is an important prognostic parameter in patients with hypertrophic cardiomyopathy (HCM). Though cardiac rhythm management (CRM) devices (e.g., ICD, pacemaker or implantable loop recorder) can detect subclinical AF, data describing the incidence of AF are rare. We therefore investigated the incidence and clinical impact of de novo and subclinical AF detected by CRM devices in patients with HCM.

Methods And Results: In our retrospective single-center study, we included patients with HCM and need for CRM devices. The primary endpoint of the study was the incidence of clinical and subclinical de novo AF. During follow-up, patients were screened for adverse events like stroke, ventricular arrhythmia, heart failure, or death. From 192 HCM patients, 44 patients received a CRM device (38 ICDs, 5 pacemakers, 1 implantable loop recorder). In 14 of these patients (32%), AF had been documented before device implantation. Thirty (68%) patients were free from AF at the time of implantation. During a median follow-up of 595 days (interquartile range, 367-890 days), de novo AF was recorded in 16 of these 30 patients (53%). Fourteen (88%) of the 16 patients with de novo AF were free from any clinical symptoms, so these patients were classified to have subclinical AF. In logistic regression analysis, age was the only significant predictor for an increased risk of AF.

Conclusion: AF is common in patients with HCM who need a CRM device. More than 50% of these patients develop de novo AF that was predominantly subclinical in our cohort.