What is the interpretation of the electrocardiogram (ECG)?

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Last updated: April 6, 2025View editorial policy

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From the Guidelines

I strongly advise against attempting to upload an ECG for interpretation in this setting, as accurate interpretation requires a qualified healthcare professional with access to the patient's medical history and the ability to perform a physical examination. To have an ECG interpreted, you should upload it through a secure medical platform or bring it directly to a healthcare provider such as a primary care physician, cardiologist, or emergency department if you're experiencing concerning symptoms. ECG interpretation requires visual examination of the waveforms to assess heart rate, rhythm, intervals, and potential abnormalities, as noted in guidelines from the American College of Cardiology/American Heart Association task force on assessment of diagnostic and therapeutic cardiovascular procedures 1. Healthcare professionals are trained to identify patterns indicating conditions like arrhythmias, ischemia, infarction, or electrolyte disturbances. For accurate interpretation, the ECG should be of good quality with minimal interference, and ideally include patient information such as age, sex, and relevant medical history.

Key Considerations for ECG Interpretation

  • The ECG provides a record of electrical activity of the heart and has many uses, including serving as an independent marker of myocardial disease, reflecting electrophysiologic, anatomic, metabolic, and hemodynamic alterations, and providing information essential for the proper diagnosis and therapy of a variety of cardiac disorders 1.
  • Interpretations, particularly interpretations of rhythm disturbances, ischemia, or infarction, require careful over-reading by a physician qualified to interpret ECGs, as emphasized by the American College of Physicians 1.
  • If you're experiencing chest pain, shortness of breath, dizziness, or palpitations, please seek immediate medical attention rather than waiting for an online interpretation.

Recommendations for Healthcare Providers

  • Continuing medical education through seminars or self-assessment programs is encouraged to keep ECG interpretation skills current in settings where physicians read ECGs infrequently, as recommended by the American College of Physicians 1.
  • Documentation of proficiency in ECG interpretation, in addition to residency training, board certification, and Advanced Cardiac Life Support training, may be desirable for interpreting ECGs when the clinical milieu of the patient is unknown 1.

From the Research

ECG Interpretation

To interpret an ECG, a stepwise approach is recommended, as outlined in 2. This involves a systematic analysis of the ECG tracing to identify any abnormalities.

When to Perform an ECG

An ECG should be performed in patients with cardiac symptoms, such as chest pain, dyspnea, palpitation, and syncope, as stated in 2. However, guidelines recommend against performing an ECG in asymptomatic patients, even if they have a higher risk of developing cardiovascular disease in the long term.

Common Uses of ECG

ECG is commonly used to detect and diagnose heart disease, particularly conditions related to abnormalities of cardiac rhythm, as mentioned in 3. It is also useful in detecting arrhythmias, such as atrial fibrillation, which is the most common tachyarrhythmia encountered in clinical practice, as discussed in 4.

Treatment of Arrhythmias

Beta blockers are often used as the first line of treatment for arrhythmias, including supraventricular tachycardia and ventricular tachyarrhythmias, as stated in 5. They work by blocking the effects of sympathetic activity on the heart, which can lead to disturbances of the heart rhythm, as explained in 6.

Key Points to Consider

  • A 12-lead ECG is the most commonly ordered cardiac test, as mentioned in 2 and 3.
  • Computerized algorithms can guide ECG interpretation, but can also be a source of erroneous information, as noted in 2.
  • A stepwise approach is recommended for ECG interpretation, as outlined in 2.
  • Beta blockers are widely used as antiarrhythmic agents, as discussed in 5 and 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

The Electrocardiogram: Still a Useful Tool in the Primary Care Office.

The Medical clinics of North America, 2019

Research

Antiarrhythmic mechanisms of beta blocker therapy.

Pharmacological research, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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