Prolonged QTc affects short-term and long-term outcomes in patients with normal left ventricular function undergoing cardiac surgery.
OBJECTIVE
Although it is known that preoperative decreased left ventricular ejection fraction (LVEF) is a risk for morbidity and mortality after cardiac surgery, there are no reliable markers of risk in patients with preserved LVEF. This study examines whether a prolonged QTc interval is associated with adverse outcomes in patients with preoperative LVEF greater than 40% undergoing cardiac surgery.


METHODS
A retrospective chart review of patients who had cardiac surgery at St. Paul's Hospital in Vancouver, Canada, between 2004 and 2009, who had a preoperative LVEF greater than 40%, was undertaken. We tested for association of preoperative prolonged QTc interval with mortality and morbidity using unadjusted and adjusted analyses.


RESULTS
Five-hundred and fifty-five patients with a preoperative LVEF greater than 40% were included in the study; 496 (89.4%) had cardiopulmonary bypass and the remainder were off pump. Preoperative prolonged QTc was associated with increased mortality at 30 days (P < .01), 90 days (P < .01), and 8 years (P < .01), and these results remained significant after adjusting for the clinical variables significantly associated with mortality (8-year odds ratio, 2.42; 95% confidence interval, 1.34-4.34; P = .003). Similar results were found when the analysis was restricted to the more homogeneous group of patients undergoing on-pump coronary artery bypass (CABG, n = 408). Prolonged QTc was also associated with prolonged intensive care unit stay (P = .02), prolonged hospital stay (P < .01), development of atrial arrhythmias (P = .02), and low cardiac output syndrome (on-pump CABG, P = .02).


CONCLUSIONS
In patients undergoing cardiac surgery and a preoperative LVEF greater than 40%, a prolonged QTc interval is associated with increased short-term and long-term mortality and increased perioperative morbidity, and therefore should be considered when assessing risk preoperatively.
Centre for Heart Lung Innovation, University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia, Canada.
Nattachai
N
Anantasit
Centre for Heart Lung Innovation, University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia, Canada.
John H
JH
Boyd
Centre for Heart Lung Innovation, University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia, Canada.
James A
JA
Russell
Centre for Heart Lung Innovation, University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia, Canada.
Christopher D
CD
Fjell
Division of Cardiovascular Surgery, University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia, Canada.
Samuel V
SV
Lichtenstein
Centre for Heart Lung Innovation, University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia, Canada. Electronic address: keith.walley@hli.ubc.ca.
Keith R
KR
Walley
D000368:Aged; D001955:British Columbia; D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000401:mortality; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D016009:Chi-Square Distribution; D001026:Coronary Artery Bypass / Q000009:adverse effects; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects; D004562:Electrocardiography; D005260:Female; D006331:Heart Diseases / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D006339:Heart Rate; D006801:Humans; D007362:Intensive Care Units; D053208:Kaplan-Meier Estimate; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011183:Postoperative Complications / Q000401:mortality / Q000628:therapy; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left