Last Updated on April 2, 2025 by Analgesia team
ECG Medical Abbreviation
An electrocardiogram (ECG or EKG) is a simple, safe, and painless test that measures the electrical activity of the heart:
How ECG is Done
Preparation
- Clothing: You’ll be asked to remove clothing from the upper half of your body to allow access to your chest.
- Skin Preparation: The technician may clean or shave areas of your skin to ensure the electrodes stick properly.
- Electrode Placement: Small, sticky patches called electrodes are placed on your chest, arms, and legs. These are connected to the ECG machine via wires.
During the Test
- Resting ECG: You’ll lie still on a bed while the machine records your heart’s electrical signals. This usually takes just a few minutes.
- Portable ECG: If a longer monitoring period is needed, a portable device may be attached to your chest, which you wear for 24–48 hours.
- Stress ECG: For exercise-related heart issues, you may be asked to walk on a treadmill or pedal a stationary bike while connected to the ECG machine.
After the Test
The electrodes are removed, which might cause slight discomfort, similar to peeling off a plaster.
The results are analyzed by a doctor to check for abnormalities in heart rhythm, rate, or electrical activity.
What it Shows
- Heart Rate and Rhythm: Whether the heartbeat is too fast (tachycardia), too slow (bradycardia), or irregular (arrhythmia).
- Heart Muscle Damage: It can show evidence of past heart attacks or ongoing ischemia.
- Electrolyte Imbalances: Abnormal levels of potassium or calcium can alter the ECG’s appearance.
- Structural or Conductive Abnormalities: Issues like hypertrophy (enlarged heart chambers) or blockages in electrical pathways.
When ECG is Used
An ECG is used in a variety of medical scenarios to assess the heart’s health and diagnose potential issues. Here’s when it’s commonly employed:
Diagnosing Symptoms
- Chest Pain: To check for heart attacks or ischemia.
- Shortness of Breath: To identify potential heart-related causes.
- Palpitations: To detect arrhythmias or abnormal heart rhythms.
- Dizziness or Fainting: To rule out cardiac conditions.
Routine Checkups
- As part of a health screening, especially for individuals with risk factors like high blood pressure, diabetes, or a family history of heart disease
Pre-Surgical Assessments
- To ensure the heart is functioning normally before undergoing surgery.
Detecting Silent Problems
- Identifying issues like electrolyte imbalances, conduction delays, or structural changes in the heart that may not yet show symptoms.
Stress Testing
- During exercise tests to determine how the heart performs under physical exertion.
It’s a simple yet powerful tool for understanding the heart’s electrical activity and health
Risks and Side Effects
There are minimal risks associated with an ECG, but some people may be sensitive to the adhesive used to attach the electrodes. This can cause mild skin irritation, but it usually resolves on its own.
ECG Result Interpretation
Steps in ECG Interpretation
1. Heart Rate: Determine the speed of the heartbeat, usually calculated from the intervals between QRS complexes.
- Normal: 60–100 beats per minute (BPM)
- Bradycardia: <60 BPM
- Tachycardia: >100 BPM
2. Heart Rhythm: Assess whether the heartbeat is regular or irregular.
- Regular rhythm suggests normal sinus activity.
- Irregular rhythm may indicate arrhythmias like atrial fibrillation.
3. P Wave Analysis: Check the shape and consistency of P waves for issues with atrial activity.
- Abnormal P waves can suggest atrial enlargement or conduction problems
4. PR Interval: Measure the time between atrial and ventricular contraction.
- Prolonged intervals can point to a heart block.
5. QRS Complex: Analyze the width and shape of the QRS complex.
- Wide QRS may signal ventricular issues or conduction delays.
- Abnormal QRS amplitude can indicate hypertrophy or infarction.
6. ST Segment: Examine for elevation or depression, which may indicate ischemia or myocardial infarction.
7. T Wave: Assess for abnormalities in shape or polarity, which can indicate electrolyte imbalances or ischemia.
8. QT Interval: Measure the time for ventricular depolarization and repolarization.
- Prolonged QT can be a marker for arrhythmias or medication effects.
The interpretation requires comparison to normal values and an understanding of underlying conditions. Results are often summarized as normal or abnormal, with detailed findings about rhythm, rate, or specific abnormalities. Physicians use this information alongside clinical symptoms to diagnose and guide treatment.
STEMI in ECG
A STEMI (ST-segment elevation myocardial infarction) appears on an electrocardiogram (ECG) as an elevation of the ST segment in at least two contiguous leads. This indicates a total blockage of a coronary artery and that the heart muscle is dying.
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- In leads V2 and V3, the ST segment is elevated by at least 2 mm (0.2 mV) in men and at least 1.5 mm (0.15 mV) in women
- In other contiguous leads, the ST segment is elevated by at least 1 mm (0.1 mV)
- There is a new left bundle branch block
- Reciprocal changes, such as ST depression in a region opposite the major vessel of injury
- De Winter T waves, which are symmetrically peaked T waves in the precordial leads with up-sloping ST depression
Treatment for STEMI
- Reperfusion therapy is required immediately
- Primary percutaneous coronary intervention is the recommended method of reperfusion
When to consult a cardiologist
- If the ECG is suspicious but not diagnostic, consult a cardiologist early