First patients in the Improve SCA clinical study were enrolled at West China Hospital and Fuwai Hospital in China. These patients may be indicated for either an implantable cardioverter defibrillator (ICD) or a cardiac resynchronization therapy defibrillator (CRT-D).

ICD administers electrical shocks or painless pacing therapy to stop the heart from quivering chaotically, while CRT-D resynchronizes the contractions of the ventricles by sending tiny electrical impulses to the heart.

The two devices stop a life-threatening fast or irregular heart rhythm that causes sudden cardiac arrest. The devices are under-utilized in developing countries with typically less than 10% of indicated patients implanted.

Dr Dejia Huang from West China Hospital in Chengdu City, Sichuan Province, China, said: "The study will provide the clinical evidence needed to help primary prevention patients at the highest risk of SCA access the therapy they need, and has the potential to eventually influence local guidelines."

The prospective, non-randomized, multicenter study will build local clinical evidence to identify already indicated ICD/CRT-D primary prevention patients with additional risk factors that put them at a highest risk for SCA.

The additional risk factors include fainting (syncope), rapid transient abnormal heartbeats starting in the bottom chambers of the heart (non-sustained ventricular tachycardia or frequent premature ventricular contractions), or, decreased function of the heart (low ejection fraction).

Medtronic’s Improve SCA study will be conducted at approximately 100 sites in more than 15 countries across Central and Eastern Europe, Asia, Middle East and Africa, India, and Latin America. The study is expected to enroll approximately 4,800 participants that will be followed for two years.

The Improve SCA study will evaluate patients meeting current Class I guidelines for ICD (or CRT-D) device implant as defined by the American College of Cardiology, American Heart Association, Heart Rhythm Society (ACC/AHA/HRS) or European Society of Cardiology (ESC).

It will test whether patients with a primary prevention indication for an ICD and one or more of these additional risk factors have the same risk of a having life threatening ventricular arrhythmia as those patients who have survived a prior episode of life threatening ventricular arrhythmia and are indicated for an ICD for secondary prevention of sudden cardiac arrest.

According to Medtronic, the study results may help clinicians in identifying and refering primary prevention patients for ICD/CRT-D therapy, and help more patients make informed decisions about receiving a defibrillator.