Are electrocardiographic Q-wave criteria reliable for diagnosis of perioperative myocardial infarction after coronary surgery?

• Published in: European journal of cardio-thoracic surgery Vol. 13; no. 6; pp. 655 - 661
• Main Authors: Svedjeholm, Rolf, Dahlin, Lars Goran, Lundberg, Claes, Szabo, Zoltan, Kågedal, Bertil, Nylander, Eva, Olin, Christian, Rutberg, Hans
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science B.V 01.06.1998; Elsevier Science
• Subjects: Aged; Biological and medical sciences; Cardiac surgery; Cardiac Surgical Procedures; Creatine Kinase - blood; Creatine phospokinase isoenzyme MB; Diagnosis; Electrocardiography; Female; Humans; Intraoperative Complications; Isoenzymes; Male; Medical sciences; MEDICIN; MEDICINE; Middle Aged; Myocardial infarction; Myocardial Infarction - blood; Myocardial Infarction - diagnosis; Postoperative Complications - diagnosis; Predictive Value of Tests; Reproducibility of Results; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the heart; Troponin - blood; Troponin T; Myocardial infarction; Electrocardiography; Troponin-T; Cardiac surgery; Diagnosis; Creatine phospokinase isoenzyme MB; Human; Infarct; Enzyme; Creatine kinase; Transferases; Coronary artery; Biological marker; Cardiovascular disease; Exploration; Coronary heart disease; Myocardial disease; Electrodiagnosis; Sensitivity; Specificity; Troponin; Surgery; Myocardium; Complication; Q wave; Comparative study
• ISSN: 1010-7940; 1873-734X; 1873-734X
• DOI: 10.1016/S1010-7940(98)00091-8

Objective: A major assumption in cardiovascular medicine is that Q-waves on the electrocardiogram indicate major myocardial tissue damage. The appearance of a new Q-wave has therefore been considered the most reliable criterion for diagnosis of perioperative myocardial infarction (PMI) in cardiac surgery. In a study, originally intended to evaluate troponin-T as a marker of PMI, analysis of our data aroused the need to address the reliability of Q-wave criteria for diagnosis of PMI. Methods: In 302 consecutive patients undergoing coronary surgery, Q-wave and other electrocardiogram (ECG) criteria were compared with biochemical markers of myocardial injury and the postoperative course. All ECGs were analysed by a cardiologist blinded to the biochemical analyses and the clinical course. Results: The incidence of positive Q-wave criteria was 8.1%. Combined biochemical (CK-MB≥70 μg/l) and Q-wave criteria were found in 1.0%. Patients with new Q-waves did not have CK-MB or troponin-T levels significantly different from those without Q-waves. More than 25% of the Q-waves were associated with plasma troponin-T below the reference level (<0.2 μg/l) on the fourth postoperative day. Q-wave criteria alone did not influence the postoperative course. In contrast, biochemical markers correlated with clinical outcome. Conclusions: The majority of Q-waves appearing after coronary surgery were not associated with major myocardial tissue damage, and according to troponin-T one-fourth of the Q-waves were not associated with myocardial necrosis. Furthermore, the appearance of Q-waves had little influence on short term clinical outcome. Therefore, the use of Q-wave criteria as the gold standard for diagnosis of PMI may have to be questioned.