Prevalence of Q-T Interval Dispersion in Type 1 Diabetes and Its Relation With Cardiac Ischemia
The EURODIAB IDDM Complications Study Group
- Massimo Veglio, MD1,
- Sara Giunti, MD2,
- Linda K. Stevens, MD3,
- John H. Fuller, MD3,
- Paolo Cavallo Perin, MD2 and
- The EURODIAB IDDM Complications Study Group
- 1Evangelico Valdese Hospital, Turin, Italy
- 2Department of Internal Medicine, University of Turin, Turin, Italy
- 3EURODIAB, Department of Epidemiology and Public Health, University College of London, London, U.K.
Abstract
OBJECTIVE—The interlead variation in duration of the Q-T interval on the surface electrocardiogram (Q-T interval dispersion [QTd]) has been shown to predict mortality in type 2 diabetic patients. We evaluated the prevalence of QTd prolongation in the EURODIAB population and its relation to corrected Q-T interval (QTc), sex, age, duration of diabetes, blood glucose control, and complications.
RESEARCH DESIGN AND METHODS—A total of 3,042 type 1 diabetic patients were studied. QTc was calculated according to the Bazett’s formula; QTc > 0.44 s was considered abnormally prolonged. QTd was calculated using the difference between the maximum and the minimum QTc in any thoracic lead. QTd >0.080 s was considered abnormally prolonged.
RESULTS—The prevalence of an increased QTd was 7%. A significant relation was observed between QTd prolongation and diastolic blood pressure (P < 0.05). A higher prevalence of QTd prolongation was observed in patients with ischemic heart disease (P = 0.004), whereas no relationship was observed with retinopathy, albumin excretion rate, or measures of somatic and autonomic neuropathy. QTc and QTd were significantly related (P = 0.001); however, a proportion of patients with normal QTd showed a prolonged QTc (>0.44 s).
CONCLUSIONS—In patients with type 1 diabetes, QTd is associated with ischemic heart disease and diastolic blood pressure but not neuropathy. Although QTd is statistically related to duration of QTc, increased QTd and increased QTc identify different patients, and their predictive value deserves prospective evaluation.
- AER, albumin excretion rate
- ECG, electrocardiogram
- IHD, ischemic heart disease
- QTc, corrected Q-T interval
- QTd, Q-T interval dispersion
Footnotes
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Address correspondence and reprint requests to Massimo Veglio, Via Mancini 15, 10131 Torino, Italy. E-mail: veglio{at}onw.net.
Received for publication 30 November 2001 and accepted in revised form 21 December 2001.
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