Reentrant ventricular outflow tract tachycardia arising from focal scar detected by delayed enhancement magnetic resonance imaging.

A 58-year-old man was referred to our emergency room with hemodynamically unstable sustained ventricular tachycardia (VT). The morphology of the VT exhibited a left bundle branch block and inferior axis deviation. He had no past history of cardiovascular disease. Echocardiography, cardiac catheterization, cardiac biopsy, gallium scintigram, myocardial scintigram, T1,T2-weighted magnetic resonance imaging (MRI), and gadolinium-enhanced cine MRI did not detect any structural heart disease or abnormal cardiac function. However, delayed-enhancement MRI (DE-MRI) detected a focal intramural scar within the septal ventricular outflow tract. An electrophysiological study revealed a sustained VT with several morphologies and the entrainment phenomenon. Radiofrequency catheter ablation to the site corresponding to the focal scar detected by DE-MRI successfully eliminated the VT.