exercise thallium scans post thrombolysis

Last reviewed 01/2018

The presence of reversible ischaemia on an exercise thallium scan in patients thrombolysed for acute myocardial infarction is a sensitive predictor for future adverse cardiac events.

100 patients who had been thrombolysed for acute myocardial infarction and were free of adverse cardiac events after 6 weeks were entered into the trial. Patients underwent exercise thallium tests and exercise ECG tests.

Of the 37 patients who showed reversible ischaemia on the exercise thallium, 33 subsequently had adverse cardiac events. The hazard ratio for patients with reversible ischaemia was 8.1 (95% intervals 2.7 to 23.8).

Of the 33 patients who showed reversible ischaemia on the exercise ECG, 13 subsequently had adverse cardiac events. The hazard ratio for patients with reversible ischaemia was 1.1 (96% intervals 0.56 to 2.2). Exercise ECG failed to predict events in 24 patients.

Traditional teaching is that an exercise ECG post-MI is useful for prognostication. This study suggests that in patients treated with thrombolysis for acute MI the investigation of choice is an exercise thallium.

Reference:

• 1) Basu, S. et al. (1996). Value of thallium-201 imaging in detecting adverse cardiac events after myocardial infarction and thrombolysis: a follow up of 100 consecutive patients. BMJ, 313, 844-8.