An inappropriately–appropriate ICD therapy: What is the mechanism and what interventions can be done?

KEY CLINICAL MESSAGE: R‐wave double counting is a rare cause of ventricular oversensing that can lead to inappropriate shocks. Optimizing device programming is essential for the avoidance of subsequent inappropriate therapies. ABSTRACT: R‐wave double counting is a rare cause of ventricular oversensing that can lead to inappropriate shocks. We present the case of a female patient, 52‐years‐old with a history of end‐stage hypertrophic cardiomyopathy. The patient suffered an implantable cardioverter‐defibrillator (ICD) shock. Cardiac device interrogation revealed ventricular tachycardia (VT) with a cycle length of 420 ms that was misclassified in the ventricular fibrillation (VF) zone owing to R‐wave double counting. Optimizing device programming is essential for the avoidance of subsequent inappropriate therapies. Possible therapeutic options are briefly presented in the case.