Characteristics of Transient ST-Elevation versus ST-Elevation and Non-ST-Elevation Myocardial Infarction

Background: Patients with acute myocardial infarctions (AMI) may present with or without ST-segment elevation (STEMI or NSTEMI, respectively) on their electrocardiogram (ECG). However, there is a third type presenting with transient ST-elevation (TSTEMI).

Objective: To characterize patients with TSTEMI on the spectrum between NSTEMI and STEMI and their outcome.

Method: Medical information regarding patients admitted to our CCU since 2010 for suspected ACS was prospectively recorded. STEMI and NSTEMI were defined as patients with a clinical presentation compatible with ischemia, persistent ST-elevation or no ST-elevation in their ECGs and positive troponin-T levels. TSTEMI was similarly defined except that their documented ST elevation was no longer present on the admission ECG to the CCU.

Results: Of 1847 AMI patients, 1072 had STEMI, 649 had NSTEMI and 126 had TSTEMI (prevalence: 6.2%). TSTEMI vs. STEMI and NSTEMI patients were younger (56.7 vs. 59.6 and 62.8 years, both p<0.01), were more frequently male (88.1 vs. 82 and 77.2%, p<0.01), hypertensive (47.6 vs. 41.2 and 25.8%, p<0.001) and smokers (72.2 vs. 53.2 and 41.8%, p<0.001). TSTEMI had less coronary involvement compared to STEMI and NSTEMI (1 VD– 40 vs. 37 and 26%, p<0.001; 2 VD- 22 vs. 35 and 33%, p<0.02; 3 VD-30 vs. 27 and 38%, p<0.001). However, TSTEMI patients had less myocardial damage (peak CPK 480 vs. 1708 p

Conclusions: Although patients with TSTEMI had a higher prevalence of some risk factors than STEMI and NSTEMI patients, they had less severe coronary disease and myocardial damage, and had a better outcome, suggesting an aborted STEMI or spontaneous coronary reperfusion of a NSTEMI which may have caused the transient ST-elevation.