What is an ECG?

• An electrocardiogram (ECG) is one of the simplest and fastest tests used to evaluate the heart. Electrodes (small, plastic patches that stick to the skin) are placed at certain spots on the chest, arms, and legs. The electrodes are connected to an ECG machine by lead wires. The electrical activity of the heart is then measured, interpreted, and printed out. No electricity is sent into the body.
• Natural electrical impulses coordinate contractions of the different parts of the heart to keep blood flowing the way it should. An ECG records these impulses to show how fast the heart is beating, the rhythm of the heart beats (steady or irregular), and the strength and timing of the electrical impulses as they move through the different parts of the heart. Changes in an ECG can be a sign of many heart-related conditions.

Why do I need an ECG?

Some reasons for your doctor to request an electrocardiogram (ECG) include:
• To look for the cause of chest pain
• To evaluate problems which may be heart-related, such as severe tiredness, shortness of breath, dizziness, or fainting
• To identify irregular heartbeats
• To help determine the overall health of the heart before procedures such as surgery; or after treatment for conditions such as a heart attack (myocardial infarction, or MI), endocarditis (inflammation or infection of one or more of the heart valves); or after heart surgery or cardiac catheterization
• To see how an implanted pacemaker is working
• To determine how well certain heart medicines are working

How to Prepare for an ECG?

• No special preparations are necessary for a standard electrocardiogram.
• Tell your doctor about any medications and supplements you take. These can often affect the results of your test