One or more implantable cardioverter defibrillator (ICD) high energy discharges delivered in response to an event other than an appropriately sensed ventricular arrhythmia meeting criteria for therapy. Examples of such events include artefactual sensing (e.g., T-wave oversensing or noise), supraventricular arrhythmias (e.g., atrial fibrillation or flutter, supraventricular tachycardia (SVT)) and sinus tachycardia.