title: Increased T-wave alternans is associated with subclinical myocardial structural and functional abnormalities in patients with type 2 diabetes.
abstract: Increased T wave alternans (TWA) represents ventricular depolarization heterogeneity and is a non-invasive marker of sudden cardiac death. This study sought to determine whether myocardial structural alteration and dysfunction in patients with type 2 diabetes mellitus (T2DM) is associated with an increased TWA.
  
  
  
  We recruited 108 T2DM patients (59.2±9.7 years and 52% male) without prior history of cardiovascular disease and normal treadmill stress testing. TWA was analyzed during treadmill testing in all standard precordial leads by time-domain method. Transthoracic echocardiography was performed to measure myocardial structural alteration by calibrated integrated backscatter (IBS), left ventricular (LV) systolic function by conventional method, and speckle tracking-derived global longitudinal strain (GLS), and LV diastolic function.
  
  
  
  A total of 29 (26.9%) patients had a high TWA of ≥47mV (defined by ≥75 percentile of the study population). Patients with and without elevated TWA had a similar LV dimension and ejection fraction. Nonetheless, patients with high TWA had a higher calibrated IBS (-15.8±4.0dB vs. -17.9±5.3dB, p=0.04), more impaired GLS (-18.4±2.0% vs. -19.3±1.4%, p=0.02), and a higher prevalence of diastolic dysfunction (60 vs. 33%, p=0.02). Multivariable analysis demonstrated that high TWA was independently associated with calibrated IBS, GLS, and LV diastolic dysfunction grading.
  
  
  
  Our results demonstrated that calibrated IBS, GLS, and LV diastolic dysfunction are independent predictors for high TWA in T2DM patients. These findings suggest that subclinical myocardial structural and functional abnormalities may contribute to high TWA in T2DM patients.
authors.affiliation: Division of Cardiology, Department of Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhen
authors.affiliation: Division of Cardiology, Department of Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Division of Cardiology, Department of Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
authors.forename: Ju-Hua
authors.initials: JH
authors.lastname: Liu
authors.affiliation: Division of Cardiology, Department of Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
authors.forename: Carmen Wing-Sze
authors.initials: CW
authors.lastname: Chan
authors.affiliation: Division of Endocrinology, Department of Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
authors.forename: Michele
authors.initials: M
authors.lastname: Yuen
authors.affiliation: Division of Endocrinology, Department of Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China; Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China; Division of Cardiology, Department of Medicine, the University of Hong Kong-Shen Zhen Hospital, Shen Zhen, China.
authors.forename: Karen Siu-Ling
authors.initials: KS
authors.lastname: Lam
authors.affiliation: Division of Cardiology, Department of Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China; Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China; Division of Cardiology, Department of Medicine, the University of Hong Kong-Shen Zhen Hospital, Shen Zhen, China. Electronic address: hftse@hkucc.hku.hk.
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
authors.affiliation: Division of Cardiology, Department of Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China; Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China; Division of Cardiology, Department of Medicine, the University of Hong Kong-Shen Zhen Hospital, Shen Zhen, China. Electronic address: khkyiu@hku.hk.
authors.forename: Kai-Hang
authors.initials: KH
authors.lastname: Yiu
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D003971:Diastole / Q000502:physiology; D004452:Echocardiography; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000503:physiopathology
keywords: Cardiac dysfunction; Diabetic cardiomyopathy; T-wave alternans