When to Get an Electrocardiogram (EKG)
An electrocardiogram (EKG) should be obtained immediately for patients with symptoms suggestive of cardiac involvement such as chest pain, syncope, palpitations, or unexplained dyspnea, and should be performed within 10 minutes of arrival at a healthcare facility for suspected acute coronary syndrome. 1
Symptomatic Indications for EKG
EKGs are strongly indicated in the following clinical scenarios:
Cardiac Symptoms
- Chest pain or symptoms suggestive of acute coronary syndrome
- Syncope or near-syncope
- Palpitations
- New or worsening dyspnea
- Extreme and unexplained fatigue, weakness, or prostration 2
- Unexplained change in the usual pattern of angina pectoris 2
Medication Monitoring
EKGs are indicated when:
- Starting medications known to cause cardiac effects
- Changing dosages of cardiac-affecting medications
- Adding potentially interacting drugs
Common medications requiring EKG monitoring include:
- Psychotropic agents (phenothiazines, tricyclic/tetracyclic antidepressants, lithium)
- Anti-infective agents (erythromycin, pentamidine)
- Antihypertensives (diuretics, ACE inhibitors, calcium channel blockers, beta-blockers)
- Antineoplastic agents
- Heart failure medications (digitalis, dopamine, dobutamine) 2
Preoperative EKG Indications
EKGs are recommended before surgery for:
- Patients with known cardiovascular disease undergoing any surgery 2
- Asymptomatic persons over 40 years of age undergoing intermediate or high-risk surgery 1
- Patients with one or more clinical risk factors (coronary artery disease, heart failure, cerebrovascular disease, diabetes, renal insufficiency) undergoing vascular surgery 1
- Patients older than 65 years with diabetes, hypertension, smoking history, peripheral vascular disease, or morbid obesity 1
Post-Procedure EKG Indications
EKGs should be obtained:
- Before and immediately after electrical or pharmacologic cardioversion
- Before hospital discharge after cardioversion 2
- After pacemaker insertion or revision
- When pacemaker malfunction is suspected
- After lead threshold maturation
- Periodically throughout the lifetime of patients with pacing systems 2
- After cardiac surgery or extensive pulmonary surgery until condition stabilizes 2
Follow-up EKG Indications
Periodic EKGs (typically yearly) are recommended for:
- Monitoring progression of known cardiovascular diseases
- Evaluating effectiveness of therapy
- Follow-up of patients at increased risk for cardiac disease 1
The appropriate interval depends on:
- Known natural history of the disease
- Patient's age
- Effectiveness of therapy
- Severity of disease at last evaluation 2, 1
When EKGs Are Not Indicated
EKGs are generally not indicated for:
- Asymptomatic patients undergoing low-risk surgery 1
- Patients receiving treatments not known to produce EKG changes 2
- Routine screening of asymptomatic individuals without risk factors 3
Important Caveats
- A normal EKG does not exclude acute coronary syndrome, occurring in 1-6% of such patients 1
- Overreliance on a normal or nonspecifically abnormal EKG in a patient with classic anginal symptoms is dangerous 4
- Serial EKGs at 15-30 minute intervals are recommended during the first hour if the initial EKG is nondiagnostic but clinical suspicion remains high 1
- Comparison with previous EKGs is valuable when available 1
Common Pitfalls to Avoid
- Relying solely on a single normal EKG to rule out cardiac disease
- Delaying EKG acquisition beyond 10 minutes in patients with suspected acute coronary syndrome
- Failing to obtain serial EKGs when symptoms persist or change
- Not considering EKG changes when initiating or changing medications 1
Following these evidence-based guidelines will help ensure appropriate use of EKGs in clinical practice, balancing diagnostic utility with resource utilization.