An 18- year old woman with hypertrophic cardiomyopathy, aborted sudden cardiac death and implanted with an implantable cardioverter defibrillator (ICD), developed progressive fragmentation of her surface 12-lead electrocardiogram (ECG). During the follow-up, she presented with multiple appropriate ICD discharges. Here, we discuss the possible association between surface fragmented ECG and the risk of ventricular arrhythmias in patients with hypertrophic cardiomyopathy.