When is an electrocardiogram (ECG) recommended?

Indications for Electrocardiogram (ECG)

An electrocardiogram (ECG) is strongly recommended as the first-choice diagnostic test for patients presenting with chest pain, dizziness, or syncope, as these symptoms may indicate life-threatening conditions such as myocardial infarction or sudden cardiac death. 1

Primary Indications for ECG

Patients with Known Cardiovascular Disease or Dysfunction

• A baseline ECG is essential during initial evaluation of all patients with known cardiovascular disease, dysfunction, or arrhythmia 1
• Serial ECGs are indicated to evaluate response to therapy, particularly when the underlying condition is evolving rapidly or is intermittent 1
• Follow-up ECGs are recommended for patients with progressive cardiovascular diseases, with frequency determined by disease severity, therapeutic response, and changes in symptoms 1
• A preoperative ECG is recommended for all patients with known cardiovascular disease undergoing cardiac or non-cardiac surgery 1

Patients with Suspected or at Risk of Cardiovascular Disease

• ECG should be obtained within 10 minutes of presentation for all patients with acute chest pain, regardless of clinical setting 2
• For patients presenting with suspected acute coronary syndrome (ACS), an immediate ECG is critical for early diagnosis and triage 3, 2
• Serial ECGs should be performed if the initial ECG is equivocal but clinical suspicion of myocardial ischemia remains high 3, 2
• In patients with palpitations or intermittent chest pain, an ECG is essential for initial evaluation 2

Specific Clinical Presentations Requiring Immediate ECG

• Patients with chest pain, especially those aged ≥30 years 4
• Patients aged ≥50 years presenting with shortness of breath, altered mental status, upper extremity pain, syncope, or generalized weakness 4
• Patients aged ≥80 years with abdominal pain or nausea/vomiting 4
• Patients with symptoms that may indicate Wellens syndrome (a pre-infarction state requiring urgent intervention) 3

ECG Monitoring and Serial Testing

• ECG monitoring should be initiated as soon as possible to detect life-threatening arrhythmias in high-risk patients 3
• Serial ECGs are crucial when evaluating:
  • Acute ischemia to assess reversal or progression 1
  • Response to medication that may produce ECG changes 1
  • Before and after electrical or pharmacologic cardioversion 1
  • Pacemaker function and programming 1

Special Considerations

• For patients with non-diagnostic initial ECG but strong clinical suspicion of ACS, consider extended ECG with additional leads (V7-V9) to identify posterior wall involvement 3
• In patients with suspected hypertrophic cardiomyopathy, an ECG may show abnormalities even at early disease stages and help differentiate from phenocopies like cardiac amyloidosis 5
• A single normal ECG does not rule out ACS when clinical suspicion is high; serial ECGs are essential in these cases 2

When ECG is Not Recommended

• Routine ECG screening is not recommended for asymptomatic patients, even those with higher risk of developing cardiovascular disease in the long term 6
• ECG is of little or no usefulness in patients receiving treatments not known to produce ECG changes or affect conditions associated with such changes 1

Common Pitfalls to Avoid

• Relying solely on computerized ECG interpretations without physician verification can lead to significant medical and legal consequences 1
• Delaying transfer to emergency department for troponin testing from office settings can worsen outcomes 2
• Failing to obtain serial ECGs when clinical suspicion of ACS remains high despite an initial normal ECG 2
• Misinterpreting ECG patterns like Wellens syndrome as non-ischemic causes of T-wave inversion 3

The ECG remains an irreplaceable first-line diagnostic tool that provides immediate information about arrhythmias, conduction defects, myocardial infarction, and other cardiac conditions that may not be available with other tests 1.