An electrocardiogram (ECG or EKG) is a non-invasive medical test that measures the electrical activity of the heart over a period of time it's one of the most common and valuable tools used in cardiology for diagnosing various heart conditions. Here's how it works and what it entails.

Principle:

The heart generates electrical impulses that coordinate its pumping action. These impulses cause the heart muscles to contract and pump blood throughout the body.

An ECG measures these electrical signals as they travel through the heart. Electrodes, typically attached to the arms, legs and chest pick up these electrical signals and transmit them to a machine that records the data as a series of waves on paper or digitally.

Procedure:

During an ECG, the patient les down comfortably while a technician attaches small adhesive electrodes to specific locations on the skin. These electrodes are connected to the ECG machine.

The machine then records the heart's electrical activity, typically over a few seconds to a few minutes

The resulting graph, called an electrocardiogram, displays the electrical patterns of the heart's different phases depolarization (contraction) and cepolarization (relaxation) of the heart muscle

Interpretation:

The ECG waveform consists of several components, including the P wave, QRS complex, and T wave.

The P wave represents atrial depolarization (contraction), the QRS complex.corresponds to ventricular depolarization (contraction), and the Twave indicates ventricular repolarization. (relaxation) Changes in the shape, size, or timing of these waves can indicate various heart conditions, such as arrhythmias (irregular heart rhythms), myocardial infarction (heart attack), electrolyte imbalances, conduction abnormalities, and structural heart defects

 Types of ECG:

Resting ECG: This is the standard ECG performed while the patient is at rest. It provides baseline information about the heart's electrical activity.

Exercise (stress) ECG: Also known as a stress test, this ECG is performed while the patient.exercises on a treadmill or stationary bike. It evaluates the heart's response to physical exertion and helps diagnose coronary artery disease and exercise-induced arrhythmias

Clinical Applications:

Diagnosis of heart rhythm disorders (arrhythmias) such as atrial fibrillation, ventricular tachycardia and bradycardia. Assessment of heart rate and rhythm abnormalties.

Detection of myocardial ischemia (lack of blood flow to the heart muscle), which may Indicate coronary artery disease.

Monitoring the effects of medications or interventions on the heart's electrical activity. Overall ECG is a valuable tool in cardiology for diagnosing heart conditions, guiding treatment decisions, and monitoring cardiac health: It's widely available, non-invasive and provides valuable insights into the heart's electrical function.