QTc interval length and QT dispersion as predictors of mortality in patients with non-insulin-dependent diabetes

Patients with non-insulin-dependent diabetes (NIDDM) are at independent risk of cardiovascular death. The reason is only partially understood. The aim of our study was therefore to evaluate the impact of corrected QT interval length (QTc) and QT dispersion (QT-disp) on mortality in a cohort of 324 Caucasian NIDDM patients. A resting 12-lead ECG was recorded at baseline. Maximum (QT-max) and minimum QT (QT-min) intervals were measured, and QT-max was corrected for heart rate (QTc-max). QT-disp was defined as the difference between QT-max and QT-min. QTc-max was 454 (376-671) ms½ (median (range)) and QT-disp 61 (0-240) ms. Prolonged QTc interval (PQTc), defined as QTc-max>440 ms½, was present in 67% of the patients and prolonged QT-disp (PQT-disp), defined as QT-disp>50 ms, was present in 51%. During the 9-year follow-up period, 100 patients died (52 from cardiovascular diseases). Thirty-seven percent of the patients with PQTc died compared with 17% with normal QTc interval (p<0.001). The Cox propo...