上室性不整脈における右房の器質的異常に伴う電気生理学的所見

Correlation of electrophysiological findings to pathological findings of the right atrium in supraventricular arrhythmia

はじめに

　今野ら^1）により心内膜下心筋生検法が考案され，広く臨床応用されるようになった。我々も心筋生検法による病理組織学的検索とHis束心電図検査（HBE）を同時に行うことにより，不整脈と心筋の組織学的変化との関係を臨床的に追求し，不整脈疾患では高頻度に心筋の器質的異常を認めたと報告^2,3）してきた。

　今回の研究は上室性不整脈疾患を対象として右房心内膜下心筋生検（右房生検）を行い，その組織所見と電気生理学的検査所見とを対比検討し，心筋の器質的異常に伴う電気生理学的異常を追求することを目的としたものである。

To study the relation between pathological tissue changes of the right atrium (RA) and electro-physiological findings, His bundle electrocardiogram (HBE) and RA endomyocardial biopsy were performed in 39 patients (Pts) with supraventricular arrhythmia. HBE was recorded at rest and during the high rate RA pacing. Immediately after the stimulation threshold of RA was measured using a bioptome as a stimulation electrode, RA biopsy was done at the same site.

Pts were classified into two groups according to the biopsy findings: Normal=19 Pts with nomal pathological RA tissue, Abnormal=20 Pts with fibrosis (14 Pts), hypertrophy (3), fatty degeneration (1), amyloidosis (1) or alcoholic cardiomyopathy (1). There were no significant difference in PA and AH intervals and in maximum corrected recovery time between Normal and Abnormal. In Abnormal, however stimulation threshold was higher (4.14 vs 2.65 volts, p<0.01) and the incidence of producing 2nd-degree AH block below RA pacing rate 120/min was higher (83% vs 33%, p<0.01) compared to Normal, suggesting the affects of tissue changes on the supraventricular conduction system. Thus, measurement of stimulation thresh-old of RA and RA pacing rate producing 2nd-degree AH block were useful in detecting the presence of the tissue changes in RA in Pts with supraventricular arrhythmia.