There are many etiologies of ST segment elevation other than MI. How often do these lead to unwarranted thrombolytic therapy or emergent angiography?

5.7 - 11%.

The most common causes of ST-segment elevation in these patients who received unwarranted thrombolytic therapy or emergency angiography was left ventricular hypertrophy, early repolarization, conduction defects, and ventricular aneurysm from old infarction.


Source

Wang, K., Asinger, R., and Marriott, H. "ST-Segment Elevation in Conditions Other than Acute Myocardial Infarction" N Engl J Med 27 Nov 2003.