慢性心不全に対するメトプロロール長期投与の効果—冠動脈疾患および拡張型心筋症での比較検討

The Long-term Effect of Metoprolol in Chronic Heart Failure:A comparison between coronary artery disease and dilated cardiomyopathy

　【目的】慢性心不全例に対するメトプロロール（M）長期投与の臨床効果を冠動脈疾患（CAD）群と拡張型心筋症（DCM）群とで比較した．【方法】心プールシンチで左室駆出率（LVEF）40％以下のCAD,DCM各15例，各30例に対しM投与前（前）と2mg／日からの少量漸増療法により維持量（60mg／日）投与1年後（後）の心機能の指標；LVEFと心室性不整脈の指標；ホルター心電図上のLown分類（L）を各群で比較した．【結果】前の値では，CAD群はDCM群よりも有意にLVEFが高値だった．前後の比較ではDCM群はCAD群と異なりLVEFが有意に増加した．しかしCAD群でもLVEFがより低い（＜30.6％）例では全例増加した点から，前のLVEFの程度による影響も考えられた．また，Lは両群とも有意に改善した．【結論】Mの長期投与はDCM群，CAD群いずれの慢性心不全例でも心機能を悪化させることなく，心室性不整脈の重症度を改善させることが確認された．

Purpose ; The effects of metoprolol (M) on the cardiac function and ventricular arrhythmia were investigated and comparison was made between coronary artery disease (CAD. n=15) and dilated cardiomyopathy (DCM, n=15) associated with chronic heart failure and de-creased left ventricular ejection fraction (LVEF) ＜40% by multiple-gated acquisition (MUGA) scan. Methods and Results ; M (60mg/day = maintenance dose) was ad-ministered by titrated methods starting from a small dose (2mg/day) in each group. LVEF, heart failure severity (NYHA classification) and Lown grade of ventricular arrhythmia severity were determined at the beginning and end of the study (1 year after stopping the maintenance dose).LVEF increased significantly after M treatment in the subjects of the DCM group. but not in those of the CAD group. However, the LVEF at the beginning in the DCM group was lower than that in the CAD group. Four patients with lower LVEF (＜30.6%) in the CAD group showed an increase in LVEF at the end of this study. The reason for this difference can he explained by the degree of reduction of the initial LVEF. The Lown grade improved significantly in both groups. Conclusions ; Long-term M treatment of CAD and DCM with chronic heart failure improved the Lown grade of ventricular arrhythmia severity without aggra-vation of cardiac function.