Background An implantable cardioverter-defibrillator (ICD) has been suggested for heart failure patients for primary prevention of sudden cardiac death. However, few data have been reported on the application of ICD as primary prevention of sudden cardiac death in China. We evaluated the value of primary prevention ICD therapy in Chinese patients with heart failure.Methods Thirty-four patients at an average age of (60.2±13.7) years seen in Peking Union Medical College Hospital were treated with ICD implantation for primary prevention of sudden cardiac death from November 2005 to July 2009. Single-chamber ICDs were implanted in 16 (47.0%) cases, and dual-chamber or cardiac resynchronization therapy defibrillators in 18 (53.0%) cases. The patients had an average left ventricular ejection fraction of (26.9±5.5)% (11% to 35%), of which 18 (53.0%) patients had ischemic cardiomyopathy and 16 (47.0%) patients had non-ischemic cardiomyopathy. All patients were followed up at three months after the implantation and every six months thereafter or when prompted by an ICD event.Results There were five (14.7%) deaths, including two of heart failure and three with a non-cardiac course, during an average follow-up of (15.0±11.9) months. Forty-one ICD therapy events were recorded, including 19 (46.3%) appropriate ICD therapies in six patients and 22 (53.7%) inappropriate ICD therapies in four patients with single chamber leads. Inappropriate ICD therapies were mainly due to supraventricular tachyarrhythmias, especially atrial fibrillation. Patients with ischemic cardiomyopathy and non-ischemic cardiomyopathy did not differ in the incidence of either appropriate or inappropriate therapy.Conclusions ICD for primary prevention of sudden cardiac death in China prevents patients from arrhythmia death. Relatively high incidence of inappropriate therapies highlights the importance of an atrial lead.