広範な伝導障害を呈した末端肥大症の1症例

A case of acronnegaly with broad conduction disturbance

　末端肥大症と心血管系合併症について，成長ホルモン（GH）の心筋に対する直接作用によるacromegalic heartdiseaseの存在が注目されている。本例は過去におけるGHの分泌異常が推察され，burn out acronnegalyと思われるが，合併不整脈として洞機能不全を伴うII度房室ブロックを晒し，その因果関係について若干の考察を加えたので報告する。

A 36-years old man with mild acromegaly who suffered from dizziness, syncope and was admitted to our hospital in 1985 because of occasional recur-rence of the dizziness and syncope, bradycardia with a heart rate of 32/min and Wenckebach or second degree AV black with sinus bradycardia on ECG. Physical examination at admission revealed the ab-sence of cardiac failure findings. Electrophysiological tests revealed a prolonged HV interval and His bundle duration in the sinus rhythm, but improve-ment in the prolonged effective refractry period (ERP) and functional refractry period (FRP) of AV node as well as of the prolonged corrected sinus node recovery time (CSRT) as a result of administration of atropin sulfate, suggesting participation of degen-eration of the conduction system and of vagotony. Myocardial biopsy demonstrated myocardial hyper-trophy and myocardial degeneration. X-ray ex-amination revealed expansion and deformation of the sella trucia, mandibular projection and thickening of the heel pad, while CT scan demonstrated the pituitary gland at the base of the empty sella. These findings, together with the fact that serum GH was normal, increasing after TRH load, sug-gested burn out acromegaly. It is thus concluded that the second degree AV block with SSS resulted from myocardial degeneration caused by the effects of GH secretion abnormalities in the past as well as from vagotony due to the autonomic nervous disturbance that occurs concomitantly with the myo-cardial change.