Which patients require an electrocardiogram (EKG)?

Indications for Electrocardiogram (EKG)

An EKG is indicated for patients with suspected or known cardiovascular disease, those presenting with cardiac symptoms, patients at high risk for cardiovascular disease, before certain surgeries, and for monitoring medication effects. 1

Patients with Symptoms

EKGs should be performed in patients presenting with the following symptoms:

• Chest pain or discomfort
• Syncope or near-syncope
• Unexplained changes in angina pattern
• New or worsening dyspnea
• Extreme fatigue, weakness, or prostration
• Palpitations 2, 1

Even when symptoms are present during acquisition of a normal or nonspecific EKG, patients still have similar rates of adverse cardiovascular events as those without symptoms during EKG acquisition. Therefore, clinicians should not rely solely on the absence of EKG abnormalities during symptoms to exclude acute coronary syndrome. 3

Patients with Known Cardiovascular Disease

EKGs are indicated for:

• Initial evaluation of all patients with diagnosed heart disease
• Patients with a change in symptoms, signs, or relevant laboratory findings
• Monitoring response to therapy
• Assessing disease progression or regression 2, 1
• Patients with implanted cardiac devices (pacemakers or defibrillators) 1

Preoperative Evaluation

According to the American College of Cardiology/American Heart Association guidelines:

• Class I indication (recommended): Patients with known heart disease, peripheral vascular disease, or cerebrovascular disease undergoing intermediate- or high-risk surgery 2
• Class I indication: Patients with one or more clinical risk factors (coronary artery disease, heart failure, cerebrovascular disease, diabetes, renal insufficiency) undergoing vascular surgery 2
• Class II indication (reasonable): Patients with no clinical risk factors undergoing vascular surgery or patients with one or more clinical risk factors undergoing intermediate-risk surgery 2
• Not indicated: Asymptomatic patients undergoing low-risk surgery 2

The Institute for Clinical Systems Improvement recommends EKGs for:

• Patients older than 65 years
• Patients of any age with diabetes, hypertension, chest pain, heart failure, smoking history, peripheral vascular disease, inability to exercise, or morbid obesity 2

Medication Monitoring

EKGs are recommended:

• After initiation of drugs known to cause EKG changes:
  • Psychotropic agents
  • Anti-infective agents
  • Antihypertensive medications
  • Antineoplastic agents
  • Heart failure medications 1
• When changing dosage of these medications
• When adding potentially interacting medications 1

High-Risk Patients Without Symptoms

EKGs should be considered for:

• Adults over 40 years old without symptoms but with cardiovascular risk factors 1
• Periodic follow-up (every 1-5 years) of patients known to be at increased risk for cardiac disease 2

Procedural Indications

EKGs are recommended:

• Before and after cardioversion procedures
• Before and after cardiac catheterization or angioplasty
• After pacemaker insertion or revision
• After cardiac surgery until condition stabilizes 1

Important Clinical Considerations

1. Interpretation requirements: EKG interpretation requires qualified physician review, as computer interpretation alone is insufficient and potentially dangerous 1

2. Normal EKG does not rule out ACS: In patients with suspected acute coronary syndrome, 1-4% of patients with normal EKGs may still have acute myocardial infarction 1

3. Risk stratification: The HEART and TIMI risk scores, which incorporate EKG findings and the first cardiac troponin, provide more diagnostic information than history, physical examination, and EKG alone for patients with suspected ACS 4

4. Frequency of follow-up EKGs: Should be determined by the responsible physician based on the known natural history of the disease, patient's age, effectiveness of therapy, and disease severity at last evaluation 1

By following these evidence-based guidelines for EKG utilization, clinicians can appropriately identify patients who would benefit from this diagnostic test while avoiding unnecessary testing in low-risk populations.