Radionuclide imaging to assess myocardial damage during open heart surgery

Technetium 99m Pyrophosphate imaging before and after open heart surgery was performed in 38 patients to estimate the incidence of peri-operative infarction. Positive images were present pre-operatively in 11 of 30 patients with coronary artery disease. In three patients the images changed from negative to positive and in two this was thought to be due to infarction produced at operation. The high incidence of positive pre-operative images emphasises that many patients with evolving myocardial infarction, unstable angina or severe heart failure are now operated upon without delay. Because many patients have positive images before surgery pre-operative and post-operative images must be compared to assess myocardial damage due to surgery.