Risk stratification of the J wave syndrome

Appearance of a J wave is a potent risk for idiopathic ventricular fibrillation (VF). The incidence of inferolateral J wave is higher in patients with idiopathic VF than that in control subjects. Patients having a higher and widespread J wave with horizontal/descending ST segments are at high risk for arrhythmic events (malignant early repolarization (ER)), and it is associated with arrhythmic storm. J wave dynamicity, fragmented QRS, and T wave abnormality will be even more high-risk signs in patients with malignant ER. Occurrence of short coupled premature ventricular contractions can be a precursor of VF and sudden death. Patients who have experienced aborted cardiac arrest or ventricular tachyarrhythmias should receive an implantable cardioverter defibrillator. Cohort studies have shown that inferolateral J wave is also a risk marker for the cardiovascular and arrhythmic events. High and widespread J wave is also a risk for the arrhythmic events in general population, but the occurrence of idiopathic VF is very rare. The incidence of the idiopathic VF will be 90:100,000 in persons with a tall J wave with a horizontal/descending ST segment. The existence of J wave will increase the risk of VF during acute ischemia or in patients with structural heart diseases. In patients with inherited arrhythmic syndrome, J wave also increases the risk of VF.