岡村 昌宏, 三明 淳一朗, 小倉 一能, 加藤 克, 飯塚 和彦, 近藤 健人, 加藤 雅彦, 山本 一博

Akihiro OKAMURA, Junichiro MIAKE, Kazuyoshi OGURA, Masaru KATOH, Kazuhiko IITSUKA, Takehito KONDO, Masahiko KATOH, Kazuhiro YAMAMOTO

鳥取大学医学部附属病院循環器内科

Department of Cardiology, Faculty of Medicine, Tottori University, Japan

キーワード :

【Background】
Left ventricular （LV） systolic dysfunction is caused by atrial fibrillation （AF）, which is referred to as tachycardia-induced cardiomyopathy （TIC）. TIC has a reversible nature of diseased condition and is diagnosed after controlling ventricular rate or restoration of sinus rhythm. Idiopathic dilated cardiomyopathy （DCM） is often accompanied by AF, and unlike TIC, DCM is an irreversible form of disease. In clinical practice, it is difficult to discriminate between TIC caused by AF and DCM with AF at the initial visit. In this study, we investigated the electrocardiographic and echocardiographic characteristics of TIC caused by AF at initial visit before controlling ventricular rate or restoration of sinus rhythm in comparison with those of DCM with AF.
【Methods】
Consecutive AF patients with first or second attacks and LV ejection fraction＜50％ were included in this study. Patients were divided into TIC group （n=5） or DCM group （n=5）. Echocardiographic and electrocardiographic characteristics and plasma B-type natriuretic peptide level （BNP） on AF attacks in both groups were analyzed retrospectively.
【Results】
LV end-diastolic dimension was significantly smaller in TIC group than in DCM group （50.4±2.5mm vs. 61.8±4.5 mm, p=0.003） while LV ejection fraction, left atrial dimension and BNP were not significantly different between the two groups. LV mass index was significantly smaller in TIC groups than in DCM group （140.2±15.5g/m2 vs. 207.6±37.8g/m2, p=0.005）. Fibrillatory wave （FW） amplitudes were significantly larger in TIC group that in DCM group （0.13±0.03mV vs. 0.07±0.03mV in lead Ⅱ, p=0.010; 0.23±0.04mV vs. 0.13±0.05mV in lead V1, p=0.003）.
【Conclusion】
LV end-diastolic dimension, LV mass index, and FW amplitude may be useful to discriminate between TIC caused by AF and DCM with AF at the initial visit.