Electrocardiography, commonly known as ECG or EKG (from the German “elektrokardiogramm”), is a non-invasive medical test that records the electrical activity of the heart over a period of time. This diagnostic procedure is used to assess the heart’s rhythm and electrical conduction, helping healthcare professionals identify various cardiac conditions and abnormalities.
During an ECG, small electrodes are placed on specific points of the chest, arms, and legs. These electrodes detect the electrical signals generated by the heart as it contracts and relaxes. The data collected by the electrodes is displayed as a graph, known as an electrocardiogram. By interpreting the patterns and intervals on the ECG, healthcare providers can gain valuable insights into the heart’s health and functioning.
Resting ECG (Standard 12-Lead ECG): This is the most common type of ECG performed during routine medical examinations. It uses ten electrodes to record electrical signals from twelve different perspectives or “leads” of the heart. A resting ECG provides a snapshot of the heart’s activity at rest and helps identify irregular heart rhythms, signs of heart disease, and previous heart attacks.
Holter Monitoring (Ambulatory ECG): Holter monitoring is a continuous ECG performed over a 24-hour period or longer. The patient wears a portable ECG device (Holter monitor) that records the heart’s electrical activity during normal daily activities and sleep. This test is helpful in diagnosing intermittent or infrequent heart rhythm abnormalities.
Event Monitoring: Similar to Holter monitoring, event monitoring is used to capture infrequent symptoms related to heart rhythm disturbances. The patient wears a portable device, but the recording is triggered manually by the patient when they experience symptoms like palpitations or dizziness.
Exercise Stress Test (Treadmill Test): An exercise stress test combines ECG monitoring with physical exercise (usually on a treadmill or stationary bike). It evaluates the heart’s response to stress and helps diagnose coronary artery disease, exercise-induced arrhythmias, and exercise tolerance.
Signal-Averaged ECG (SAECG): SAECG is a specialized ECG that uses computer-based signal averaging techniques to enhance the detection of subtle electrical abnormalities in the heart. It is particularly useful in assessing patients at risk of ventricular arrhythmias.
Cardiac Event Recorder: This portable device is used for longer-term ECG monitoring (weeks to months). It is typically prescribed to patients with unexplained or infrequent symptoms to capture cardiac events for diagnosis.
Vector ECG (VCG): Vectorcardiography is a technique that provides a three-dimensional representation of the heart’s electrical activity. It offers additional insights into the heart’s conduction pathways and can be used to study cardiac hypertrophy and other complex heart conditions.
