Evaluation of Spodick's Sign and Other Electrocardiographic Findings as Indicators of STEMI and Pericarditis
Michael D Witting1, Kami M Hu1, Aaron A Westreich2
1Department of Emergency Medicine, University of Maryland School of Medicine, Baltimore, Maryland.
Insights
Spodick's sign is more common in pericarditis than ST elevation myocardial infarction (STEMI), but not exclusive to it. ST depression and lead differences are better indicators for differentiating these conditions.
Area of Science:
- Cardiology
- Electrocardiography
- Diagnostic Medicine
Background:
- Distinguishing ST elevation myocardial infarction (STEMI) from pericarditis using electrocardiograms (ECGs) is crucial.
- Spodick's sign (T-P segment depression) has been proposed as an indicator for pericarditis but lacks validation.
Purpose of the Study:
- To determine the frequency of Spodick's sign in patients with STEMI and pericarditis.
- To identify other ECG findings that differentiate between STEMI and pericarditis.
Main Methods:
- Retrospective chart review of patients diagnosed with STEMI or pericarditis.
- ECG analysis by an expert, assessing for Spodick's sign and other specific ST-T wave abnormalities.
- Statistical analysis using odds ratios (OR) and 95% confidence intervals (CI) to quantify associations.
Main Results:
- Spodick's sign was present in 5% of STEMI patients and 29% of pericarditis patients.
- ST depression (OR 31), ST elevation in lead III greater than lead II (III > II) (OR 21), and absence of PR depression (OR 12) showed the strongest association with STEMI.
Conclusions:
- While Spodick's sign is associated with pericarditis, its presence in STEMI cases limits its specificity.
- ST depression, III > II, and absence of PR depression are highly effective ECG markers for differentiating STEMI from pericarditis.
Background:
Patients with ST elevation on electrocardiogram (ECG) could have ST elevation myocardial infarction (STEMI) or pericarditis. Spodick's sign, a downsloping of the ECG baseline (the T-P segment), has been described, but not validated, as a sign of pericarditis.
Objective:
This study estimates the frequency of Spodick's sign and other findings in patients diagnosed with STEMI and those with pericarditis.
Methods:
In this retrospective review, we selected charts that met prospective definitions of STEMI (cases) and pericarditis (controls). We excluded patients whose ECGs lacked ST elevation. An authority on electrocardiography reviewed all ECGs, noting the presence or absence of Spodick's sign, ST depression (in leads besides V1 and aVR), PR depression, greater ST elevation in lead III than in lead II (III > II), abrupt take-off of ST segment (the RT checkmark sign), and upward or horizontal ST convexity. We quantified strength of association using odds ratio (OR) with 95% confidence interval (CI).
Results:
One hundred and sixty-five patients met criteria for STEMI and 42 met those for pericarditis. Spodick's sign occurred in 5% of patients with STEMI (95% CI 3-10%) and 29% of patients with pericarditis (95% CI 16-45%). All other findings statistically distinguished STEMI from pericarditis, but ST depression (OR 31), III > II (OR 21), and absence of PR depression (OR 12) had the greatest OR values.
Conclusions:
Spodick's sign is statistically associated with pericarditis, but it is seen in 5% of patients with STEMI. Among other findings, ST depression, III > II, and absence of PR depression were the most discriminating.
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