Risks of Appropriate Implantable Cardioverter Defibrillator Therapy and Hospitalization Are Increased Around Device‐Detected Atrial High‐Rate Episodes Longer Than 6 min

Background The prognostic significance of device‐detected atrial high‐rate episodes (AHRE) in patients with implantable cardioverter defibrillator (ICD) remains poorly understood. We aimed to evaluate whether device‐detected AHRE ≥ 6 min is temporally associated with appropriate ICD therapy and cardiac hospitalization. Methods We studied consecutive patients with dual chamber or cardiac resynchronization therapy ICD with predominantly sinus rhythm and followed with remote monitoring (RM). Risk of ICD therapy and hospitalization was compared inside a 60‐day peri‐AHRE period (from 30 days before to 30 days after AHRE detection) with risk outside the peri‐AHRE period. We included appropriate ICD therapies only. Adjusted extended Cox model with time‐varying exposure analysis was used to assess potential associations between AHRE and ICD therapies and hospitalization. Results We included 882 patients. Median age 67 years [interquartile range; 59–73], 81% male, 76% had coronary artery disease, and 61% CRT‐D. The 30‐day risk of appropriate ICD shock was 0.8% inside the peri‐AHRE period compared with 0.2% outside the peri‐AHRE period (adjusted hazard ratio [aHR] 3.04; 95% confidence interval [CI]: 1.67–5.52; p < 0.001). The 30‐day risk of any appropriate ICD therapy was increased inside compared with outside the peri‐AHRE period (1.2% vs. 0.4%, aHR 1.71 [95% CI: 1.14–2.57], p = 0.01). Cardiac hospitalization was higher inside the peri‐AHRE period (3.1% vs. 1.0%, aHR 1.42 [95% CI: 1.05–1.92], p = 0.02). Conclusion The risk of appropriate ICD shock is three‐fold elevated during a 60‐day period surrounding AHRE detection. A comparable temporal pattern was noted for cardiac hospitalizations, supporting that AHREs may indicate clinical worsening of heart disease.