title: Significance of new Q waves and their location in postoperative ECGs after elective on-pump cardiac surgery: An observational cohort study.
abstract: The clinical significance of new pathological Q waves after on-pump cardiac surgery is uncertain.
  
  
  
  To determine whether or not either the occurrence per se or the location of new pathological Q waves after on-pump cardiac surgery is associated with 12-month, all-cause mortality and/or major adverse cardiac events (MACEs).
  
  
  
  Observational cohort study.
  
  
  
  Single university hospital from January 2007 to October 2010.
  
  
  
  Consecutive adult patients undergoing elective on-pump cardiac surgery with MACE-free survival until at least the 7th postoperative day and available ECGs both preoperatively and on the 7th postoperative day (n = 1464). We conducted a subgroup analysis in patients undergoing isolated coronary artery bypass grafting (n = 740).
  
  
  
  Our primary endpoint was 12-month, all-cause mortality and/or MACE, defined as acute coronary syndrome, cardiac arrest, congestive heart failure or re-vascularisation at 12 months. Using logistic regression, we examined the prognostic value of new pathological Q waves according to the Minnesota ECG Code, adjusting for the EuroSCORE II, cardiopulmonary bypass time and peak postoperative troponin T concentrations.
  
  
  
  We included 1464 patients (74% men; mean ± SD age 66 ± 10 years) and observed 103 (7.0%) all-cause deaths and/or MACEs at 12 months. A total of 236 patients (16.1%) had definite or probable new pathological Q waves according to the Minnesota ECG Code. The occurrence of new pathological Q waves per se was not associated with our primary endpoint [adjusted odds ratio, 0.970 (95% confidence interval, 0.540 to 1.648)]. However, the occurrence of a new pathological Q wave in V1 to V5 (anterior) was a strong independent predictor for poor outcome [adjusted odds ratio, 3.461 (95% confidence interval, 1.501 to 7.242)].
  
  
  
  The current analysis suggests that for patients undergoing elective on-pump cardiac surgery, only new pathological Q waves in V1 to V5 (anterior) in the 7th postoperative day ECG are associated with 12-month, all-cause mortality and/or MACE.
  
  
  
  Clinicaltrials.gov identifier: NCT00468598.
authors.affiliation: From the Department for Anesthesia, Surgical Intensive Care, Prehospital Emergency Medicine and Pain Therapy (EM, DB, JF, EES, GALLB); Division of Cardiac Surgery, Basel University Hospital (MG); and Basel University Medical School, Basel, Switzerland (MDS, MF).
authors.forename: Eckhard
authors.initials: E
authors.lastname: Mauermann
authors.forename: Daniel
authors.initials: D
authors.lastname: Bolliger
authors.forename: Jens
authors.initials: J
authors.lastname: Fassl
authors.forename: Martin
authors.initials: M
authors.lastname: Grapow
authors.forename: Esther E
authors.initials: EE
authors.lastname: Seeberger
authors.forename: Manfred D
authors.initials: MD
authors.lastname: Seeberger
authors.forename: Miodrag
authors.initials: M
authors.lastname: Filipovic
authors.forename: Giovanna A L
authors.initials: GA
authors.lastname: Lurati Buse
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000639:trends; D015331:Cohort Studies; D017558:Elective Surgical Procedures / Q000009:adverse effects / Q000639:trends; D004562:Electrocardiography / Q000379:methods / Q000639:trends; D011183:Postoperative Complications / Q000175:diagnosis / Q000503:physiopathology; D011446:Prospective Studies