title: Frequency and cause of transient QT prolongation after surgery.
abstract: Patients undergoing surgery are often exposed to QT-inciting factors that may increase the risk for complications. We evaluated the clinical characteristics and outcomes of patients with QTc ≥500 ms within the first 24 hours after surgery as identified by an institution-wide electrocardiogram alert system. From November 2010 to June 2011, 470 patients exhibited an electrocardiographically isolated QTc ≥500 ms. QT prolongation after surgery was the setting for >1 of every 10 QTc alerts (59 patients). We determined the presence of QT prolonging medical conditions, drugs, electrolyte abnormalities, and the surgical patient's clinical outcome. The average preoperative QTc of the 59 patients demonstrating perioperative QT prolongation was 463 ± 56 ms with a postoperative QTc increase of 54 ± 37 ms. Most patients (n = 48, 83%) had ≥1 known QT-inciting factor before surgery. Compared with presurgical findings, there was a significant increase in pro-QTc score after surgery (1.8 ± 1.5 vs 3.5 ± 2.0, p <0.01) indicating a greater burden of perioperative QT-inciting factors. In conclusion, nearly all cases of QT prolongation could be explained by known etiologic or iatrogenic factors suggesting that maladaptive cardiac repolarization is most likely not a transient, postoperative stress response and may be avoided by altering clinical management.
authors.affiliation: Mayo Medical School, Mayo Clinic, Rochester, Minnesota.
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Joyce
authors.affiliation: Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota.
authors.forename: J Martijn
authors.initials: JM
authors.lastname: Bos
authors.affiliation: Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota.
authors.forename: Kristina H
authors.initials: KH
authors.lastname: Haugaa
authors.affiliation: Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Tarrell
authors.affiliation: Division of Health Care Policy and Research, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Morlan
authors.affiliation: Division of General Internal Medicine, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota.
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Caraballo
authors.affiliation: Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota; Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota; Division of Pediatric Cardiology, Department of Pediatrics, Mayo Clinic, Rochester, Minnesota. Electronic address: ackerman.michael@mayo.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Ackerman
mesh_terms: D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D015994:Incidence; D008133:Long QT Syndrome / Q000453:epidemiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D011183:Postoperative Complications; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013514:Surgical Procedures, Operative / Q000009:adverse effects*