What are the indications for ordering an electrocardiogram (EKG)?

Indications for Ordering an Electrocardiogram

Order an ECG immediately for any patient presenting with chest pain, syncope, dizziness, palpitations, or dyspnea—these symptoms may signal life-threatening conditions including myocardial infarction, arrhythmias, or sudden cardiac death. 1

Class I Indications (ECG is First Choice and Essential)

Acute Symptom Presentations

• Chest pain of any character requires immediate ECG to exclude acute coronary syndrome, as approximately 10-20% of chest pain presentations represent myocardial infarction 2
• Syncope or near-syncope mandates ECG evaluation to identify arrhythmias or conduction abnormalities 1
• Palpitations warrant ECG to diagnose rhythm disturbances 1
• Dyspnea of unclear etiology requires ECG assessment 3
• New or worsening anginal symptoms necessitate ECG evaluation 1
• Extreme unexplained fatigue, weakness, or prostration should prompt ECG ordering 1

Patients with Known or Suspected Cardiac Disease

• Any change in symptoms, signs, or laboratory findings in patients with established cardiovascular disease 1
• Suspected cardiac disease based on abnormal physical findings, prior abnormal ECGs, or abnormal imaging studies 1
• Patients at increased risk for cardiac disease due to conditions like diabetes, pulmonary disease, peripheral vascular disease, thyroid disease, muscular dystrophies, collagen vascular disease, sarcoidosis, amyloidosis, or drug abuse 1

Monitoring Drug Therapy

• Before and during therapy with cardioactive drugs including antiarrhythmics, to assess QRS duration, QT interval prolongation, or proarrhythmia 1
• Drugs known to produce cardiac effects: psychotropic agents (phenothiazines, tricyclic antidepressants, lithium), anti-infectives (erythromycin, pentamidine), antihypertensives (diuretics, ACE inhibitors, calcium channel blockers, beta-blockers), and antineoplastic agents 1
• Chemotherapy with doxorubicin or other cardiotoxic agents requires serial ECG monitoring 1

Post-Procedural Monitoring

• After coronary angioplasty or intracardiac procedures until stable and before discharge 1
• After pacemaker insertion or revision, with periodic follow-up throughout the device lifetime 1
• After electrical or pharmacologic cardioversion of any tachyarrhythmia 1
• After cardiac surgery or extensive pulmonary surgery including transplantation 1

Preoperative Evaluation

• All patients >40 years old undergoing any surgery 1
• All patients with known cardiovascular disease undergoing cardiac or noncardiac surgery 1
• Transplant donors and non-cardiopulmonary transplant recipients 1
• Dialysis patients at initiation and annually thereafter 3

Class II Indications (ECG is Reasonable but Not Essential)

• Patients with implanted pacemakers or antitachycardia devices for routine follow-up 1
• Periodic follow-up (every 1-5 years) of patients at increased risk for cardiac disease development 1
• Hemodynamically insignificant congenital or acquired heart disease in preoperative setting 1
• Minimal to mild hypertension in preoperative evaluation 1
• Drugs altering serum electrolyte concentrations (e.g., diuretics in hypertensive patients) 1

Class III Indications (ECG Not Useful or Indicated)

• Patients <30 years old without cardiac symptoms, risk factors, or known disease undergoing surgery 1
• Asymptomatic adults with no interval change in symptoms, signs, or risk factors who had a normal recent ECG 1
• After resolution of chest pain in follow-up when patient is asymptomatic 1
• Therapy not known to produce ECG changes or affect cardiac conditions 1
• Benign cardiovascular conditions unlikely to progress in adult patients at routine follow-up visits without clinical changes 1

Critical Diagnostic Considerations

Serial ECGs Are Essential When:

• Initial ECG is non-diagnostic but clinical suspicion for acute coronary syndrome remains high 3, 4
• Symptoms persist or change during observation 3
• Monitoring response to thrombolytic or anti-ischemic therapy in acute ischemia 1
• Approximately 5% of patients with normal initial ECGs discharged from emergency departments ultimately have acute MI or unstable angina 4

High-Risk ECG Patterns Requiring Urgent Action:

• ST-segment elevation or depression indicating acute ischemia—54.2% of these patients have myocardial infarction 2
• Wellens syndrome (deep symmetrical T-wave inversion in precordial leads) indicates critical proximal LAD stenosis requiring urgent angiography 4
• Hyperacute T-waves, terminal QRS distortion, or loss of precordial T-wave balance may represent early STEMI 5

Important Caveats:

• Computer interpretations must always be verified by a qualified physician, particularly for rhythm disturbances, ischemia, or infarction 1
• Clinical context is mandatory for accurate ECG interpretation—the same ECG pattern may occur in different pathophysiologic states 1, 3
• Patients with normal ECGs and chest pain have extremely low risk (1.3%) for acute MI but still require risk stratification based on cardiac risk profile 2
• For acute life-threatening symptoms, in-person emergency evaluation is preferable to remote ECG interpretation 3