METHODS

Between 1993 and February 2006, 160 consecutively referred patients with HCM (age⩽ 16 years) underwent clinical evaluation using 12-lead ECG, two-dimensional, M-mode and Doppler echocardiography, Holter monitoring and cardiopulmonary exercise testing using previously described methods. 2 Risk markers for sudden cardiac death (SCD) were:(1) family history of SCD;(2) unexplained syncope;(3) abnormal blood pressure response during upright exercise;(4) non-sustained ventricular tachycardia; and (5) severe left ventricular hypertrophy (⩾ 30 mm). 2 Patients with previous cardiac arrest or with⩾ 2 risk factors were considered for ICD implantation. 2 All patients who underwent ICD implantation during this period were included in this study.