Sudden cardiac arrest linked to early repolarization

8 May 2008

MedWire News: Individuals who have experienced sudden cardiac arrest from arrhythmias have a higher prevalence of early repolarization than individuals without heart disease, research shows.

"These findings are potentially relevant to the assessment of patients with syncope or a family history of sudden death," the authors write in the New England Journal of Medicine.

Early repolarization is a common electrocardiographic finding that is generally considered to be benign, but recent studies have suggested it is associated with sudden cardiac arrest, the authors explain.

Michel Ha?saguerre (Université Bordeaux, France) and colleagues assessed the prevalence of electrocardiographic early repolarization in 206 patients who were resuscitated after cardiac arrest due to idiopathic ventricular fibrillation and 412 individuals without heart disease.

Early repolarization was defined as an elevation of the QRS-ST junction of at least 0.1 mV from baseline in the inferior or lateral lead.

Patients were significantly more likely than controls to experience early repolarization, at 31% versus 5% (p<0.001). After adjustment for age, gender, ethnic background, and level of physical activity, patients were 10.9 times more likely than controls to have early repolarization.

Patients with early repolarization were more likely to be male and to have a history of syncope or sudden cardiac arrest during sleep than patients without repolarization.

During a mean follow-up period of 61 months, defibrillator monitoring showed that patients with early repolarization were more likely than those without this abnormality to have recurrent ventricular fibrillation, at 41% versus 23% (hazard ratio=2.1, p=0.008).

"Our results suggest a relationship between early repolarization and sudden cardiac arrest, a conclusion that is at odds with the seemingly benign nature of this common phenomenon," say Ha?saguerre and co-workers.

N Engl J Med 2008; 358: 2016-2023