Grant: Project Grant

Each year, more than 30,000 Canadians undergo cardiac surgery. Myocardial infarction, known commonly as a heart attack, is a frequent major cardiac complication after any type of heart surgery. Diagnosing a heart attack after open-heart surgery is challenging: the classic symptoms of chest pain and shortness of breath are commonly masked by painkillers or can be confused with post-operative discomfort. The markers of heart damage in the blood (troponins) are always elevated after heart surgery due to the intervention on the heart during the surgery. The electrocardiogram (ECG), which traces the heart's electrical activity, is a test often used in the diagnosis of myocardial infarction. However, its value after heart surgery is unclear because manipulating the heart, as done during heart surgery, can cause ECG changes making it difficult for physicians to know if a heart attack has occurred. We are conducting a study, called the Vascular events In Surgery patIents cOhort evaluatioN (VISION) Cardiac Surgery study, at 23 hospitals in 11 countries and we have almost completed recruitment of 15,000 patients who have had cardiac surgery. Information about these patients, including their medical history, type of heart surgery, and how well they recovered was collected. We measured troponins and collected ECGs before and after surgery for all patients. All patients were followed for one year after surgery. For this proposed study, experts will review the ECGs for all patients, both before and after their heart surgery, for signs of heart injury or damage. This will determine whether ECG changes increase the ability of physicians to diagnose a heart attack after heart surgery and whether physicians can predict which patients may die due to this complication.