Electrocardiogram (ECG or EKG)

An Electrocardiogram (ECG or EKG) is a non-invasive medical test used to measure the electrical activity of the heart. It records the electrical signals produced by the heart as it beats, providing valuable information about the heart's rhythm and function.

How it Works

The ECG test involves attaching small electrodes to the skin on the chest, arms, and legs. These electrodes detect the electrical activity of the heart and transmit it to a machine that records the signals. The recorded signals are then printed out as a graph, allowing healthcare professionals to interpret the results.

Types of ECG

There are several types of ECG tests, including:

• Resting ECG: This is the most common type of ECG test, performed while the patient is at rest.
• Stress ECG: This test is performed while the patient is exercising or under physical stress, typically on a treadmill.
• Ambulatory ECG (Holter monitor): This test involves wearing a portable ECG device for an extended period, usually 24-48 hours, to record the heart's activity during daily activities.
• Event monitor: This test involves wearing a portable ECG device that records the heart's activity when symptoms occur.

What it Measures

An ECG measures various aspects of the heart's electrical activity, including:

• Heart rate: The number of beats per minute.
• Rhythm: The pattern of the heartbeat, including any irregularities or arrhythmias.
• P wave: The electrical signal that triggers the heartbeat.
• QRS complex: The electrical signal that represents the contraction of the ventricles.
• T wave: The electrical signal that represents the relaxation of the ventricles.
• Interval measurements: The time between different parts of the heartbeat, such as the PR interval and QT interval.

Clinical Uses

ECG tests are used to:

• Diagnose heart conditions, such as arrhythmias, coronary artery disease, and cardiac conduction disorders.
• Monitor the effectiveness of treatments, such as medications or pacemakers.
• Screen for heart disease in asymptomatic individuals, particularly those with risk factors.
• Assess cardiac function before surgery or other medical procedures.

Risks and Limitations

The ECG test is generally safe and painless. However, it may not detect all heart conditions, and results should be interpreted in conjunction with other diagnostic tests and clinical evaluation.