Influence of Diabetes and/or Myocardial Infarction on Prevalence of Abnormal T-Wave Alternans
Methods: We performed a case-control cross-sectional study in 140 patients referred for routine exercise testing within a large multispecialty clinic. All patients with a history of DM and MI status within the past year were eligible: group 1 (no DM or MI), group 2 (DM only), group 3 (MI only), group 4 (DM and MI). Patients performed a symptom-limited Bruce protocol exercise test with assessment of TWA by the spectral method using commercially available equipment. We used published criteria for the blinded interpretation of TWA; all tests not unequivocally negative were considered abnormal.
Results: Age and gender were similar in all groups. The prevalence of abnormal TWA in groups 1–4 was 24%, 20%, 48%, and 62%, respectively (between group P = 0.002). Logistic regression analysis in all patients showed that abnormal TWA was related to prior MI [OR (95% CI): 4.0 (1.8–8.9), P < 0.001] but not to prevalent DM [0.9 (0.4–1.8), P = 0.72]. In patients with DM, the prevalence of abnormal TWA was related to reduced ejection fraction (P = 0.034) but not to BMI, DM duration, glycemic control, insulin use, or the presence of microvascular complications.
Conclusion: The presence of DM alone does not increase risk of abnormal TWA. Prospective studies are required to establish the prognostic value of TWA in patients with DM.
Document Type: Research Article
Affiliations: 1: Department of Cardiovascular Medicine, Lahey Clinic Medical Center, Bington, MA 2: The Cardiovascular Research Group, Division of Cardiovascular and Endocrine Sciences, University of Manchester, and The Manchester Diabetes Centre, Manchester Royal Infirmary, Manchester, UK
Publication date: October 1, 2009