A Case of Idiopathic Ventricular Fibrillation Triggered by Premature Ventricular Contraction Originating from Right Ventricular Outflow Tract

Abstract

A 28 year-old man without any heart disease suddenly fell down in a train and was admitted to our hospital after complete resuscitation by automated external defibrillator. Various cardiac examination were performed to clarify the cause of cardiopulmonary arrest. Coronary angiography showed normal coronary artery, and acetylcholine provocation test and exercise stress test were negative. No structural heart disease was revealed by cardiac MRI and echocardiogram. Brugada syndrome was suspected because of mild ST-segment elevation in the right precordial leads, however intravenous pilsicainide did not elicit typical coved type pattern. On a continuous electrocardiogram monitoring, there were frequent monofocal premature ventricular contractions (PVCs) originating from right ventricular outflow tract (RVOT), and some of them developed into nonsustained polymorphic ventricular tachycardia. Considering from these results, he was highly suspected having idiopathic ventricular fibrillation (VF) triggered by PVC of RVOT origin. Radiofrequency catheter ablation (RFCA) was performed and no polymorphic ventricular tachycardia was induced by any stimuli after RFCA. An implantable cardioverter defibrillator (ICD) was also implanted, and no shock has been delivered after hospital discharge. We experienced malignant type of idiopathic VF triggered by PVC from RVOT, and combination therapy of RFCA and ICD would be effective in this case.