When is an electrocardiogram (ECG) recommended for patients with suspected cardiac issues?

From the Guidelines

An electrocardiogram (ECG) is recommended for patients with suspected cardiac issues when they present with symptoms such as chest pain, particularly during, or immediately after, an episode suggestive of myocardial ischaemia, as stated in the 2024 ESC guidelines for the management of chronic coronary syndromes 1.

Key Indications for ECG

• Chest pain triggered by emotional stress, dyspnoea or dizziness on exertion, pain in the arms, jaw, neck, or upper back, or fatigue should be considered as potential angina equivalents, as suggested by the 2024 ESC guidelines 1.
• A resting 12-lead ECG is recommended in all individuals reporting chest pain, unless an obvious non-cardiac cause is identified, as recommended by the 2024 ESC guidelines 1.
• ECGs are also valuable in emergency situations where acute coronary syndrome (ACS) is suspected, and should be acquired and reviewed for ST-segment–elevation myocardial infarction (STEMI) within 10 minutes of arrival, as stated in the 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guideline for the evaluation and diagnosis of chest pain 1.

Benefits of ECG

• ECGs provide immediate information about heart rate, rhythm, and electrical conduction, helping to detect arrhythmias, myocardial ischemia or infarction, electrolyte abnormalities, and structural heart abnormalities.
• They are non-invasive, painless, quick to perform, and relatively inexpensive, making them an excellent first-line diagnostic tool for cardiac evaluation that can guide further testing or treatment decisions.

Clinical Considerations

• The 2024 ESC guidelines recommend a detailed assessment of cardiovascular risk factors, medical history, and symptom characteristics in individuals with suspected chronic coronary syndrome 1.
• The 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guideline recommends measuring cardiac troponin (cTn) as soon as possible after presentation in patients with acute chest pain and suspected ACS 1.
• Serial ECGs and cardiac troponin levels may be necessary in patients with ongoing symptoms and high clinical suspicion for ACS, as recommended by the 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes 1.

From the Research

ECG Recommendations for Suspected Cardiac Issues

• An electrocardiogram (ECG) is recommended for patients with suspected cardiac issues, particularly those presenting with symptoms compatible with acute coronary syndrome 2, 3.
• The ECG should be read along with the clinical assessment of the patient to determine the presence, extent, and severity of myocardial ischemia 2, 4.
• ST segment elevation (and ST depression in leads V1-V3) in patients with active symptoms usually indicates acute occlusion of an epicardial artery with ongoing transmural ischemia, and these patients should be triaged for emergent reperfusion therapy 2.
• ECG interpretation is an essential part of the initial evaluation of patients with symptoms suspected to be related to myocardial ischemia, along with focused history and physical examination 4.
• Electrocardiography should be performed within 10 minutes of presentation in patients with suspected acute coronary syndrome 5.

Specific ECG Findings

• ST elevation MI is diagnosed with ST segment elevation in two contiguous leads on electrocardiography 5.
• Non-ST elevation ACS can be diagnosed in the absence of ST segment elevation, with an elevated cardiac troponin level required for diagnosis 5.
• Up-sloping ST-segment depression with positive T waves is increasingly recognized as a sign of regional subendocardial ischemia associated with severe obstruction of the left anterior descending coronary artery 4.
• Widespread ST-segment depression, often associated with inverted T waves and ST-segment elevation in lead aVR during episodes of chest pain, may represent diffuse subendocardial ischemia caused by severe coronary artery disease 4.

Additional Testing

• In some patients with negative electrocardiography findings and normal cardiac biomarkers, additional testing may further reduce the likelihood of coronary artery disease 5.
• Cardiac catheterization is the standard method for diagnosing coronary artery disease, but exercise treadmill testing, a stress myocardial perfusion study, stress echocardiography, and computed tomography are noninvasive alternatives 5.
• Magnetocardiography (MCG) may be beneficial for the early triage of patients with acute chest pain, particularly in the absence of specific findings on ECG and positive biomarker tests 6.