ヒス束内ブロックの臨床的，電気生理学的検討およびその長期予後

Clinical, electrophysiological and long-term follow-up studies in patients with His bundle block

　房室ブロックの障害部位がヒス束以下にある場合，従来よりペースメーカー（PM）植込み適応とされ，その障害部位診断は臨床的に重要なこととされている。とくにヒス束内ブロック（BHブロック）は補充収縮がnarrow QRSを示す場合が多いため，ヒス束上ブロック（AHブロック）との鑑別にはヒス束心電図（HBE）が必須である。最近HBEの普及によりBHブロックが少なくないことが注目されている。しかし多数例のBHブロックについて臨床的・電気生理学的に検討した報告は少なく，とくにその長期予後について検討した報告は本邦ではみられない。そこで我々は，BHブロックの自験例42例について検討してその特徴を明らかにし，さらにヒス束下ブロック（HVブロック）と比較し，興味ある所見を得たので報告する。

In 42 patients with intra His bundle block, clini-cal, electrophysiological and long-term follow-up studies were performed and the results were compair-ed in 67 patients with infra His bundle block. Patients with intra His bundle block ranges in age from 34 to 78 years (mean ages 65 years), and 76% were females. Faintness or syncope had occurred in 83%. Hypertension was present in 21 patients (50%) and cardiomegaly as defined by a cardiothoracic ratio>0.5 in 8 patients (19%). Only 3 patients had apparent underlying heart disease. In electrophysiological data, sinus node recovery time prolonged abnormally in one patient, the A-H interval was greater than 120msec in 2 patients and the H'V interval greater than 55msec in one patient. It was considered that intra His bundle block may rarely accompany other conduction dis-turbance. 40 patients (95%) had received artificial cardiac pacemaker. In long-term follow-up 2 patients with artificial cardiac pacemaker died, one with congestive heart failure and the other with a cere-brovascular accident. One of the 2 patients without artificial cardiac pacemaker died suddenly. An arti-ficial cardiac pacemaker therapy is recommended in patient with intra His bundle block due to pre-vent further development of symptoms and sudden death.