抄録
The purpose of this study was to test a hypothesis that T-wave alternans (TWA) is improved in association with an improvement in cardiac sympathetic nervous system and systolic function by oral β-blocker therapy in patients with non-ischemic heart disease (NIHD). TWA testing, 123I-metaiodobenzylguanidine (MIBG) imaging and echocardiography were performed at the baseline and 3 months after β-blocker therapy in 26 patients with NIHD and positive TWA. The alternans voltage (Valt), the heart-to mediastinal-ratio on the early (e-H/M) and delayed (d-H/M) images, the washout rate (WR), the left ventricular ejection fraction (LVEF), and the calculated rate of change by β-blocker therapy in each parameter (ie, ΔValt, Δe-H/M, Δd-H/M, ΔWR and ΔLVEF) were measured. After therapy, TWA turned negative in 8 patients (group A) and remained positive in 18 (group B); Valt was significantly decreased in group B (p<0.001). In group A, e-H/M, d-H/M and LVEF were significantly increased (e-H/M: p<0.05, d-H/M and LVEF: p<0.01), as were e-H/M and LVEF in group B (p<0.05). There were significant correlations between ΔValt and Δe-H/M (r=-0.61, p<0.01), Δd-H/M (r=-0.82, p<0.0001), ΔWR (r=0.60, p<0.01) and ΔLVEF (r=-0.70, p<0.01). In patients with NIHD, the TWA is improved in association with the improvement in cardiac sympathetic nervous system abnormalities and left veantricular systolic dysfunction by β-blocker therapy. (Circ J 2003; 67: 821 - 825)
