An ECG, or electrocardiogram, is a test that records the electrical activity of the heart over time using electrodes placed on the skin. It produces a graph that shows the heart's electrical signals, which control the heartbeat and cause the heart chambers to contract and pump blood. This graph helps healthcare providers assess heart rate, rhythm, and detect abnormalities such as arrhythmias, heart attacks, or other heart conditions.
How ECG Works
The heart's electrical impulses, initiated by the sinoatrial node, spread through the atria and ventricles, causing them to contract. The ECG measures the voltage changes on the skin caused by this electrical activity, which appears as waves on the graph—specifically the P wave (atrial contraction), QRS complex (ventricular contraction), and T wave (ventricular relaxation).
Uses of an ECG
ECGs are commonly used to:
- Check heart rate and rhythm
- Detect heart attacks or ischemia
- Identify arrhythmias (irregular heartbeats)
- Monitor heart conditions and effects of medications
- Assess the heart's chamber size and position in some cases.
The test is simple, painless, quick, and widely available in healthcare settings, sometimes also integrated into wearable devices like smartwatches.
