The Case:
A 49-year-old M without relevant PMHx presented for a month of abdominal pain and post-prandial emesis. He denied chest pain or shortness of breath. Triage vitals were within normal limits, and the following ECG was obtained. He denied any chest pain or shortness of breath now or in the recent past.
The patient’s troponin was undetectable. His labs were unremarkable aside from a lipase of 1,226. A CT abdomen/pelvis with contrast was remarkable for a low attenuating lesion within the pancreas with downstream pancreatic ductal dilation. Inflammatory changes were noted. The lesion was ultimately negative for malignancy. The patient had a repeat ECG at one month (Figure 2).
Figure 2. ECG 1-month from index visit.
Interpretation:
The first ECG was notable for Generalized ST elevations (STE) (II, IIII, aVF, V4 V5, V6) with an upwardly concave ST segment morphology, ST depressions (aVR, V1, V2), ST segment/T wave ratio >0.25 (III, aVF) & ST segment/T wave ratio <0.25 (II, V4, V5, V6), Notched J point inV4, Normal sinus rhythm, Normal axis, and Normal intervals.
The second ECG was notable for STE of lateral precordial leads (V4 V5, V6) with an upwardly concave ST segment morphology & ST segment/T wave ratio <0.25, Resolution of ST depressions, Flattening of T wave (III, aVF), Notched J point in V4, Normal sinus rhythm, Normal axis, and Normal intervals.
Discussion:
The patient was ultimately diagnosed with pericarditis. Interestingly, his index ECG displays findings of both benign early repolarization (BER) and pericarditis. BER and pericarditis are conditions that result in STE in the absence of myocardial infarction (1). In any case of STE, you should presume it is a result of an ST elevation myocardial infarction (STEMI). Some features that suggest STEMI include ST depression other than aVR and V1, STE in lead III greater than lead II, and the presence of convex or straight ST segment morphology (2). A concave appearance suggests a non ischemic source of STE. These different morphologies can be seen in Figure 3 (3).
Figure 3. Example STE morphologies categorized by their association with ischemic versus non-ischemic etiologies.
BER and pericarditis both will have concave ST segment morphology (2). Pericarditis typically consists of generalized STE, PR depression, aVR and V1 ST depressions, normal T wave amplitude, ST segment/T wave ratio >0.25, dynamic ECG changes over weeks, and Spodick’s sign. Spodick’s sign (i.e., TP downsloping of at least 1 mm), notably, is estimated to be observed in 29% of cases of pericarditis and 5% of cases of STEMI (4). BER typically consists of STE in the precordial leads, prominent T waves, ST segment/T wave ratio <0.25, a notched J point or “fish hook” in V4, and a stable ECG over time. Notably, this patient’s ECG displays findings of both. Reviewing the patient’s ECG, you will note a concave ST morphology, which suggests a non-ischemic source. Following this, you will note generalized STE with ST depressions in aVR and V1, suggesting pericarditis. In the patient’s limb leads, you will see an ST segment/T wave ratio >0.25 in the inferior limb leads, followed by a ratio of <0.25 in the lateral precordial leads, suggesting both pericarditis and BER. Further, a notched J point in V4 is consistent with baseline BER. Pericarditis is further suggested by dynamic changes occurring in his 1-month ECG, with flattening of the inferior limb leads and normalization of the ST segment being consistent with expected changes in pericarditis (4).
Take away points:
In any case where you are unsure, treat STE as STEMI first
STEMI is likely if T wave morphology is convex or straight, if reciprocal ST depressions are present, or if STE is greater in lead III than lead II
Pericarditis is likely in the presence of generalized STE, ST depressions in aVR and V1, PR depressions, ST segment/T wave ratios >0.25, or dynamic ECG over weeks
BER is likely in the presence of STE is limited to the precordial leads, prominent T waves, ST segment/T wave ratio <0.25, a notched J point in lead V4, or stable ECG from previous and the following weeks
Authored by Jose Reyes, MD
References:
Burns E, Buttner R. The ST Segment. Life in the Fast Lane. March 16, 2022. https://litfl.com/st-segment-ecg-library/
Burns E, Buttner R. Pericarditis. Life in the Fast Lane. March 10, 2021. https://litfl.com/pericarditis-ecg-library/
Starling M, Brady WJ. Electrocardiographic Differential Diagnosis of ST Segment Elevation. Anesthesia Key. July 15, 2023. https://aneskey.com/electrocardiographic-differential-diagnosis-of-st-segment-elevation/#c25-fea-0001
Buttner R, Cadogan M. Spodick sign. Life in the Fast Lane. June 28, 2022. https://litfl.com/spodick-sign/