Prognostic importance of exercise thallium uptake by the lungs

The value of thallium-201 imaging as compared with clinical and exercise variables in predicting cardiac events for patients with suspected or confirmed coronary artery disease was studied in 525 consecutive patients referred for thallium exercise testing. During a mean follow-up period of 4.8 years, 105 cardiac events occurred, including 25 deaths from cardiac causes, 33 myocardial infarctions, and 47 coronary artery bypass procedures performed more than 90 days after thallium testing. Increased thallium uptake by the lungs during exercise, an indicator of left ventricular dysfunction, was superior to clinical, exercise, and other thallium-imaging variables in identifying patients at high risk for cardiac events.