Abstract 2614: Can We Differentiate Between ST Elevation Myocardial Infarction And Non-Ischemic Causes of ST Elevation by Analyzing the Presenting Electrocardiogram?
Background: One of the strategies to shorten the time for reperfusion of ST elevation (STE) acute myocardial infarction (STEMI) is prehospital wireless transmission of ECGs to experienced cardiologists. However, non-ischemic STE (NISTE) is common and found in 10 –15% of patients (pts). There are conflicting results on the ability to differentiate ischemic from nonischemic STE. We studied the ability of experienced electrocardiographers from North America (NA), Europe and Israel to differentiate between STEMI and NISTE in a sample of 116 ECGs showing STE.
Methods: 116 consecutive ECGs showing STE (≥0.1mV at the J point) in ≥ 2 adjacent leads of ≥18 years old pts were studied. Pts with bundle branch block or ventricular rhythm, or those within 1 week of cardiothoracic surgery were excluded. Thirteen experienced cardiologists were asked to decide based on the ECG and presence of compatible symptoms whether they would send each pt for primary percutaneous intervention (PPCI) for STEMI, and if not why.
Results: Of the 116 pts only 8 had STEMI. All 8 underwent PPCI. PPCI was recommended by individual readers in 7.8%–33.0% of the pts, with a mean 16.2% by the NA readers and 22.1% by the other readers (p=.004). Individual sensitivity for STEMI ranged from 50% to 100% (mean 71% for the NA readers and 80% for the other readers; p=.26). Individual specificity ranged from 71% to 97% (mean 88% for the NA readers and 82% for the other readers, p=.004). There was a wide variation in the distribution of reasons for diagnosing NISTE among readers. STE secondary to LVH was used in 7–31% of the ECGs; STE secondary to conduction defects was diagnosed in 0 –15%; early repolarization was diagnosed in 7–33%, Normal variant (STE mainly in V2-V3) was used in 11% to 54%, no reciprocal changes was used in 0 – 83% of the patients; concave STE was used in 0 –32%; STE secondary to old myocardial infarction was used in 5–25% , spontaneously reperfused STEMI was used in 0 –14%; pericarditis was diagnosed in 0 –17%; Brugada syndrome in 0 – 4%; no STE was noted in 0 –27%; and other causes were listed in 0 –72%.
Conclusions: Unexpectedly, we found wide variations among experienced electrocardiographers in reading ECGs with STE and differentiating STEMI from NISTE with significant regional differences.