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

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.