This is especially true when seen as a new ECG finding in a patient with acute symptoms. On the other hand - a c oved shape ( = “frowny”-configuration ) to ST elevation is more likely to suggest ischemia ( P anel A in Figure-1 ).The whole clinical picture needs to be considered. True "smiley"-shaped ST elevation in selected leads that is not out-of-proportion to QRS amplitude in the same lead - and, which occurs in the absence of large Q waves and ST depression are factors that may favor a non-ischemic cause - but which can not be depended upon as definitive.
SAW TOOTH PATTERN ECG SERIAL
C linical C orrelation is essential ! ALL BETS are OFF - IF the patient with upward concavity (ie, “ smiley”-configuration) ST elevation presents with new-onset worrisome chest pain! In this case - clinical decision making depends on a constellation of evaluative factors (ie, details of the history, exam, serial ECGs, troponins, stat Echo at the bedside, etc.).In general - in a setting in which ECGs are done for some purpose other thanassessment of acute cardiac-sounding chest pain - ST elevation with a “ smiley ” -shape ( = upward concavity), especially if seen in association with J - p oint n otching and in the absenceof other findings suggestive of acute ischemia (ie, Q waves, reciprocal ST depression) - will most often indicate a benign repolarization pattern ( P anel B in Figure-1 ).Up to half of LAD occlusions have concave ST segments, and overall non-concavity (upwardly straight or convex) is optimistically 77% sensitive for OMI of all MI sites (including inferior), but is far less sensitive for anterior OMI. Academic Emergency Medicine 8 (10): 961–67.Ĭoncavity (aka "upward concavity") is just one small piece of pattern recognition of OMI, and is not reliable to assuage concern by itself. Electrocardiographic ST Segment Elevation: The Diagnosis of Acute Myocardial Infarcton by Morphologic Analysis of the ST Segment. looked at all sites of MI and found that non-concave morphology had sensitivity and specificity of 77% and 97%, with PPV and NPV of 94% and 88%.īrady, W. Electrocardiographic Differentiation of Early Repolarization from Subtle Anterior ST-Segment Elevation Myocardial Infarction.īrady et al. In anther study of 355 LAD occlusions, only 36 of 355 LAD occlusions were excluded as "obvious" due to non-concave morphology: Upwardly concave ST segment morphology is common in acute left anterior descending coronary artery occlusion. In actuality, 40-50% of acute LAD occlusion have upwardly concave ST segment morphology in all of V2-V5. We are taught in medical school that concave upward ST segment morphology is a feature of benign STE, pericarditis, etc. He was found to have proximal LAD occlusion, but other outcome details are not available. I received this also by telemetry, and again we agreed with their plan of the nearest cath center and activated their cath lab protocol. V5 has very diminished voltage and poor quality, suggesting some combination of lead misplacement and/or physical object between it and the patient (hair, defibrillation pad, medical cables, clothing, etc.). STEMI criteria met by the STE in V6, I, and aVL. I was unable to get back in touch with them for the outcome. Before our conversation was finished, the patient went into VF arrest and they hung up. There was another cath center closer than our institution, so we agreed they should go there and advised they activate their cath lab immediately. I received this ECG via telemetry from an ambulance far from our hospital. Sinus bradycardia with first degree heart block present, clearly high risk for worsening bradycardia and/or heart blocks. V1 may be in a tug-of-war between STD from posterior involvement and STE from possible RV involvement. V2 shows STD indicating posterior involvement. Obvious STEMI and OMI with massive STE in the inferior and lateral leads, even extending back into V3.Īll STE has concave upward (smiley face) morphology. Here are two striking examples from a single shift highlighting the fallibility of the standard "smiley face" or upwardly concave ST segment morphology "rule".
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