J Wave: Different Characteristics in Two Cases with Ventricular Arrhythmias

J wave or early repolarization has been associated with the risk of ventricular tachyarrhythmias, and its risk stratification is to be established. Case 1: A 51-year-old man without structural heart disease was admitted because of near syncope due to repeated episodes of very rapid non-sustained monomorphic VT (∼240 bpm). His ECG showed J waves in the inferior and lateral leads, and J waves persisted after the administration and were not affected by pilsicainide or epinephrine. VT was mapped to the free wall of right ventricular outflow tract. Case 2: A 74 year-old man developed ventricular fibrillation after successful coronary artery bypass graft surgery. His preoperative ECG showed small J waves in the inferior and lateral leads. During the stay in ICU, J waves were dramatically augmented and led to VF. After the restoration of sinus rhythm by a DC shock, they decreased. The dynamicity and relation of the influence to J wave on the ventricular arrhythmias may be different.