What is the accuracy of a 12-lead Electrocardiogram (ECG) in diagnosing ST-Elevation Myocardial Infarction (STEMI) immediately following Return of Spontaneous Circulation (ROSC)?

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Last updated: December 17, 2025 • View editorial policy

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Accuracy of 12-Lead ECG Immediately After ROSC for STEMI Diagnosis

A 12-lead ECG obtained immediately after ROSC has moderate but imperfect accuracy for diagnosing STEMI, with sensitivity of 63-88% and specificity of 65-81%, and the false-positive rate is significantly higher when the ECG is acquired within the first 7 minutes after ROSC. 1, 2

Guideline-Based Approach

The American Heart Association mandates obtaining a 12-lead ECG as soon as possible after ROSC to determine whether acute ST elevation is present (Class I, LOE B). 3 This recommendation drives the decision for emergency coronary angiography, as coronary angiography should be performed emergently for OHCA patients with suspected cardiac etiology and ST elevation on ECG (Class I, LOE B-NR). 3

Diagnostic Performance Data

Overall Accuracy Metrics

The diagnostic accuracy varies significantly across studies:

  • In a 2008 study, the post-ROSC ECG showed sensitivity of 88% (95% CI 74-96%), specificity of 69% (95% CI 51-83%), positive predictive value of 77%, and negative predictive value of 83%. 2

  • More recent 2020 data using expanded ECG criteria demonstrated sensitivity of 63%, specificity of 81%, positive predictive value of 61%, and negative predictive value of 83%. 4

  • A 2016 multicenter study found sensitivity of 74% (95% CI 62-84%) and specificity of 65% (95% CI 53-75%) for predicting STEMI. 5

Critical Timing Factor

The timing of ECG acquisition after ROSC dramatically affects accuracy. ECGs obtained ≤7 minutes after ROSC have an 18.5% false-positive rate compared to 7.2% at 8-33 minutes and 5.8% beyond 33 minutes. 1 This represents a statistically significant difference (OR 0.34 for 8-33 minutes vs ≤7 minutes, 95% CI 0.13-0.87, P=0.02; OR 0.27 for >33 minutes vs ≤7 minutes, 95% CI 0.15-0.47, P<0.001). 1

Factors Affecting ECG Reliability

Perfusion Status

Low peripheral perfusion index (PI) after ROSC is independently associated with false-positive ECG findings for STEMI. 6 The false-positive rate differs significantly across perfusion tertiles: 28.6% in the lowest tertile (PI 0.2-1) versus 3.7% in the highest tertile (PI 2.6-6.9), p=0.04. 6 When adjusted for cardiac arrest duration, low perfusion remains significantly associated with false-positive ECG (OR 0.2,95% CI 0.1-0.6, p<0.001). 6

Metabolic Abnormalities

Despite markedly abnormal metabolic milieu (pH <7.1, lactate >2 mmol/L, or potassium <2.8 or >6.0 mEq/L), which was present in 77% of post-ROSC patients, the initial ECG retains statistically significant predictive accuracy for angiographic culprit lesions. 4 The predictive accuracy remains similar between initial and follow-up ECGs even in the presence of severe metabolic derangements. 4

Clinical Decision Algorithm

For ECGs Showing ST Elevation:

  1. If the ECG is obtained ≤7 minutes after ROSC and shows STEMI criteria, consider delaying repeat ECG acquisition by at least 8 minutes or obtaining a follow-up ECG before making definitive catheterization decisions. 1

  2. If peripheral perfusion index is available and falls in the lowest tertile (<1), recognize the 28.6% false-positive rate and consider clinical context more heavily. 6

  3. Despite these limitations, emergency coronary angiography remains the Class I recommendation for ST elevation on ECG after ROSC with suspected cardiac etiology. 3

For ECGs Without ST Elevation:

Emergency coronary angiography is reasonable for select patients (electrically or hemodynamically unstable) who are comatose after OHCA of suspected cardiac origin but without ST elevation on ECG (Class IIa, LOE B-NR). 3

Common Pitfalls

Computer-assisted ECG interpretation should never be used as the sole means to diagnose STEMI due to high false-negative rates (Class III: Harm, LOE B-NR). 3 It may only be used in conjunction with physician or trained provider interpretation. 3

The pre-hospital ROSC-ECG is a suboptimal diagnostic tool with only 65% positive predictive value, supporting the approach of referring all comatose OHCA survivors of suspected cardiac origin to tertiary heart centers with acute coronary angiography capability, even without ST elevations. 5

Practical Implications

The accuracy of the out-of-hospital ECG and that registered on hospital admission is essentially the same, meaning there is no diagnostic advantage to waiting for hospital arrival before ECG interpretation. 2 However, waiting 8-33 minutes after ROSC before ECG acquisition significantly reduces false-positive rates without compromising sensitivity for true STEMI. 1

References

3
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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