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Sensitivity and specificity of QTc dispersion for identification of risk of cardiac death in patients with peripheral vascular disease

Abstract Objective: To determine whether QTc dispersion, which is easily obtained from a standard electrocardiogram, can predict those patients with peripheral vascular disease who will subsequently suffer a cardiac death, despite having no cardiac symptoms or signs. Design: Patients with peripheral vascular disease were followed up for five years after they had had coronary angiography, radionuclide ventriculography, and their QTc dispersion calculated from their 12 lead electrocardiogram. Subjects: 49 such patients were then divided into three groups: survivors (34), cardiac death (12), and non-cardiac death (3). Main outcome measure: Survival. Results: The mean (SD; range) ejection fractions were similar in all three groups: survivors 45.9 (11.0; 27.0-52.0), cardiac death 44.0 (7.90; 28.5-59.0), and non-cardiac death 45.3 (4.55; 39.0-50.0). QTc dispersion was significantly prolonged in the cardiac death group compared with in the survivors (86.3 (23.9; 41.0-139) v 56.5 (25.4; 25.0-164); P=0.002). A QTc dispersion >/=60 ms had a 92% sensitivity and 81% specificity in predicting cardiac death. QTc dispersion in patients with diffuse coronary artery disease was significantly (P<0.05) greater than in those with no disease or disease affecting one, two, or three vessels. Conclusions: There is a strong link between QTc dispersion and cardiac death in patients with peripheral vascular disease. QTc dispersion may therefore be a cheap and non-invasive way of assessing the risk of cardiac death in patients with peripheral vascular disease. Key messages Key messages A QTc dispersion of 60 ms had a 92% sensitivity and an 81% specificity of predicting cardiac death over the next five years in patients with peripheral vascular disease QTc dispersion was most prominent in those with diffuse coronary disease Measurements of QTc dispersion should help in deciding whether cardiac investigations and treatments should be undertaken in individual patients as well as helping to plan the most appropriate treatment for their peripheral vascular disease