右室流出路起源の持続性心室頻拍を伴うサルコイドーシスの1例

A Case of Cardiac Sarcoidosis with Sustained Ventricular Tachycardia Originating from the Outflow Tract of the Right Ventricle

要旨

　患者は33歳，男性．2年前に肺サルコイドーシスと診断されている．約24時間持続する激しい動悸のために来院．意識清明で血圧低下はなかった．心電図上，心拍数は190/分台のwide QRS頻拍を認め，pilsicainide静注により頻拍は停止した．心エコー図上，右室壁運動低下，拡大を認めたが，左室壁運動異常や局所的な壁菲薄化はなかった．心臓カテーテル検査では正常冠動脈で，左心機能は正常であった．その後も同様の発作を繰り返すため，電気生理学的検査を施行した．頻拍は右室流出路の瘢痕組織周辺から発生するリエントリー性持続性心室頻拍であり，カテーテルアブレーションにより消失した．右心室生検では慢性炎症細胞浸潤を伴った線維化，類上皮細胞が認められたが，巨細胞は認められなかった．基礎疾患として，FDG-PET，Gaシンチでは心臓サルコイドーシスを示唆する所見が得られなかったが，既往歴や右室生検，MRI，右室電位所見からその存在が疑われた．

Summary

　A 33-year-old man was admitted to Osaka Prefectural Habikino Hospital because of palpitation sustained for 24 hours. He had had a pulmonary sarcoidosis for two years, confirmed by transbronchial lung biopsy. On admission this time, he had remained conscious and normotensive. The results of physical examination were unremarkable, except for sinus tachycardia(heart rate, 190 beats/min). An electrocardiograph showed wide QRS tachycardia, which returned to normal sinus rhythm under the treatment of intravenous injection of pilsicainide. Echocardiography revealed dyskinetic with dilatation of the right ventricle. In contrast, the left ventricle showed normal contraction. Coronary angiography was normal, and left ventriculography showed normokinesis. Thereafter, he repeatedly experienced ventricular tachycardia. He was transferred to the National Cardiovascular Center for evaluation by an electrophysiologic study, which revealed re-entrant sustained ventricular tachycardia originating from the outflow tract of the right ventricle. Catheter ablation was performed successfuly. A portion of the fibrosis with chronic inflammatory cell infiltration and epithelioid cell was deserved on the right ventricular endomyocardial biopsy. However granuloma with multinuclear giant cells was not detected. Neither gallium-67 nor 18F-fluoro-2-deoxyglucose positron emission tomography showed abnormal uptake in the myocardium. In this case, cardiac sarcoidosis of the right ventricle was suspected because of the patient's past history and findings of the right ventricular biopsy, magnetic resonance imaging, and electrophysiologic study.