Understanding Electrocardiograms (ECG/EKG)

• ECG stands for Electrocardiogram.
• Also referred to as EKG, which comes from the German term Elektrokardiogramm.
• Electrocardiogram is a noninvasive test which records the electrical activity of the heart over time.

Purpose

• Used to detect and analyze heart problems.
• Can help determine the cause of chest pain, shortness of breath, or irregular heartbeats.
• ECGs are used to monitor heart health, and the effectiveness of certain treatments.
• ECGs play a critical role in diagnosing heart attacks, arrhythmias, and other cardiac conditions.
• Can also assess the effects of medications or devices on the heart.

How it Works

• An ECG machine records the heart’s electrical signals with small sensors attached to the skin.
• Electrodes are placed on the chest, arms, and legs.
• Electrodes detect the tiny electrical changes on the skin arising from the heart muscle's electrophysiological activity.
• The electrical signals are amplified and displayed as a series of waves on a graph.
• The ECG tracing represents the heart’s electrical activity during each heartbeat.
• Doctors interpret these wave patterns to understand the heart's condition.

Components of an ECG

• The ECG tracing consists of several components, P wave, QRS complex, and T wave.
• The P wave represents the electrical activity associated with the contraction of the atria, the upper chambers of the heart.
• The QRS complex represents the electrical activity associated with the contraction of the ventricles, the lower chambers of the heart.
• The T wave represents the repolarization, or recovery, of the ventricles.
• Other components, such as the PR interval and ST segment, provide additional information about the timing and conduction of electrical signals in the heart.

Procedure

• An ECG is a painless and noninvasive procedure.
• During the test, the patient lies down on an examination table.
• A technician or healthcare provider attaches the electrodes to the patient’s chest, arms, and legs.
• The patient needs to remain still and relaxed during the recording.
• The ECG machine records the heart’s electrical activity for a short period, typically a few minutes.
• After completion, the electrodes are removed, and the results are analyzed by a healthcare professional.

Interpretation

• A trained healthcare professional, such as a cardiologist, interprets the ECG tracing.
• They analyze the shape, size, timing, and rhythm of the different waves and intervals.
• Abnormalities in the ECG tracing can indicate various heart conditions, such as arrhythmias, ischemia, or heart attack.
• The ECG findings are considered along with the patient’s medical history, symptoms, and other test results to arrive at an accurate diagnosis.

Types of ECGs

• There are different types of ECGs, including resting ECG, stress ECG, and Holter monitor.
• A resting ECG is recorded while the patient is at rest.
• A stress ECG is performed while the patient exercises on a treadmill or stationary bike to assess the heart’s response to physical activity.
• A Holter monitor is a portable ECG device that continuously records the heart’s electrical activity for 24-48 hours or longer, providing a more comprehensive assessment of heart rhythm.

Limitations

• ECGs are valuable diagnostic tools but have certain limitations.
• An ECG only captures a brief snapshot of the heart’s electrical activity.
• Some heart conditions may not be evident on a resting ECG and may require stress testing or continuous monitoring.
• ECGs may not always be accurate in detecting all heart problems, and other tests may be necessary to confirm a diagnosis.
• Factors such as electrode placement, patient movement, and underlying medical conditions can affect the accuracy of the ECG tracing.