Incidence of Device-Detected Atrial Fibrillation and Long-Term Outcomes in Patients With Hypertrophic Cardiomyopathy.

Atrial fibrillation (AF) is a common complication of hypertrophic cardiomyopathy (HC) and associated with adverse clinical outcomes, such as thromboembolisms. Cardiac implantable electronic devices (CIEDs) enable early detection of AF. The aim of this study was to assess the incidence of device-detected AF and the impact on long-term outcomes in patients with HC. The cohort consisted of 132 patients (63% men, mean age 52 ± 16 years) with a diagnosis of HC and a CIED. Follow-up started at the date of CIED implantation to assess the incidence of device-detected AF. Patients with persistent AF at the time of implantation were excluded from the analysis of the incidence of AF. End points were all-cause and cardiac mortality, device-detected AF, and thromboembolism (stroke, transient ischemic attack, or peripheral arterial embolism). In total, 114 patients were in sinus rhythm at time of CIED implantation. During the median 2.8 (interquartile range 1.2 to 5.4) years of follow-up, device-detected AF occurred in 29 patients (25%), resulting in an annual incidence of 7.0%/year. Device-detected AF led to a change in the clinical management in 22 patients (76%). Anticoagulation therapy was started in 13 (45%), antiarrhythmic medication in 9 (31%), and electrical cardioversion in 8 (28%) patients. Six patients (5%) suffered a thromboembolic complication. All-cause mortality was 27 (20%), and cardiac mortality was 21 (16%). A history of AF at time of implantation was an independent predictor of cardiac death (hazard ratio 4.7, p = 0.003). In conclusion, the incidence of device-detected AF in patients with HC was 7.0%/year, leading to a change in clinical management in the majority (76%) of cases to reduce the risk of thromboembolic complications. These findings stress the importance of AF detection in HC and advocate vigilant interrogation of the device.