QTc dispersion is prolonged in patients with early postoperative adverse cardiovascular events and those with silent myocardial ischemia

Objective: To determine if increased QT interval dispersion (corrected and not corrected for heart rate) is associated with perioperative silent myocardial ischemia or postoperative adverse cardiovascular events. Design: Blinded retrospective observational study. Setting: University hospital. Participants: One hundred eighty-one perioperative patients receiving general anesthesia for elective major vascular or orthopedic surgery. Interventions: None. Measurements and Main Results: QT dispersion, corrected and uncorrected for heart rate, was prolonged in patients suffering significant myocardial ischemia up to 48 hours assessed by Holter ECG monitoring, for early cardiac morbidity and all early cardiac events (including mortality) up to 1 month postoperatively. There were no significant changes in patients showing early cardiovascular mortality or late cardiac morbidity or mortality between 1 and 12 months postoperatively. Morbidity and mortality were determined from clinical notes, laboratory investigations, and autopsy when available. QT dispersion performed poorly as a screening test to identify those who subsequently developed early adverse cardiovascular outcomes. Conclusions: QT dispersion is prolonged in those at risk of early adverse cardiovascular events but is a poor screening tool. (C) 2004 Elsevier Inc. All rights reserved.