Effect of long-term beta-blocker therapy on microvolt-level T-wave alternans in association with the improvement of the cardiac sympathetic nervous system and systolic function in patients with non-ischemic heart disease.
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 beta-blocker therapy in patients with non-ischemic heart disease (NIHD). TWA testing, (123)I-metaiodobenzylguanidine (MIBG) imaging and echocardiography were performed at the baseline and 3 months after beta-blocker therapy in 26 patients with NIHD and positive TWA. The alternans voltage (V(alt)), 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 beta-blocker therapy in each parameter (ie, deltaV(alt), deltae-H/M, deltad-H/M, deltaWR and deltaLVEF) were measured. After therapy, TWA turned negative in 8 patients (group A) and remained positive in 18 (group B); V(alt) 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 deltaV(alt) and deltae-H/M (r=-0.61, p<0.01), deltad-H/M (r=-0.82, p<0.0001), deltaWR (r=0.60, p<0.01) and deltaLVEF (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 ventricular systolic dysfunction by beta-blocker therapy.
Murata
Mariko
M
Division of Cardiovascular Medicine, Department of Medical Bioregulation, Yamaguchi University School of Medicine, Japan.
Harada
Masahiko
M
Shimizu
Akihiko
A
Kubo
Makoto
M
Mitani
Reo
R
Dairaku
Yuka
Y
Matsumoto
Tomo
T
Matsuzaki
Masunori
M
D000200:Action Potentials / Q000187:drug effects*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000188:drug therapy / Q000503:physiopathology / Q000517:prevention & control; D004594:Electrophysiology; D005260:Female; D006321:Heart / Q000294:innervation / Q000503:physiopathology; D006329:Heart Conduction System / Q000187:drug effects; D006331:Heart Diseases / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology; D013599:Systole / Q000187:drug effects*; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000188:drug therapy
D000319:Adrenergic beta-Antagonists