Occurrence of Multiple Fibrofatty Replacements Exclusively in the Left Ventricle of a Patient With Monomorphic Sustained Ventricular Tachycardia
A 34-year-old man presented with cardiovascular syncope with sustained ventricular tachycardia (VT). ECG showed VT with morphologically right bundle-branch block with a-superior-axis. Cardioversion and endotracheal intubation were performed. After resolution of VT, a 12-lead ECG showed sinus rhythm, normal axis deviation, and isolated premature ventricular contraction of right bundle-branch block morphology with a-superior-axis. The transthoracic echocardiogram showed regional abnormality of contraction in the posterior area of the left ventricle with no abnormality of the right ventricle. Obstructive coronary heart disease was excluded by angiography but left ventriculography demonstrated regional contraction abnormality in the anterolateral left ventricle. Electrophysiologically, nonsustained VT induced by programmed ventricular stimulation had similar morphology as the wide QRS tachycardia on admission, but sustained VT was not reproducibly induced. Furthermore, supraventricular tachycardia with aberrant conduction was absent, which suggests that the wide QRS tachycardia could be VT. ECG-gated multislice computed tomography (Figure 1) revealed focal low-density areas (mean, ≈−80 HU) indicative of fatty infiltration in the septum and the epicardium in the posterior and lateral wall of the left ventricle; however, fat infiltration was absent in the right ventricle myocardium. Compared with the low-density area in the posterior wall, part of the low-density area in the interventricular septum was abnormally enhanced (arrowhead, Figure 1B) in the late phase, which suggests the presence of fibrosis around fat infiltration.
Biopsy of left ventricular posterior wall revealed fibrofatty replacements (arrows, Figure 2); right ventricle biopsy was not performed. QRS waveform suggested VT was likely caused by arrhythmia that resulted from ventricular dysplasia. A cardioverter defibrillator was implanted and its proper discharge for sustained VT was confirmed.