How you prepare

Before you get an ICD, your doctor will order several tests, which may include:

• Electrocardiography (ECG or EKG). An ECG is a quick and painless test that measures the electrical signals that make your heart beat. Sticky patches (electrodes) are placed on your chest and sometimes your arms and legs. Wires connect the electrodes to a computer, which displays the test results. An ECG can show if your heart is beating too fast, too slow or not at all.
• Echocardiography. This noninvasive test uses sound waves to create pictures of your heart in motion. It shows your doctor the size and structure of your heart and how blood is flowing through your heart.

• Holter monitoring. A Holter monitor is a small, wearable device that keeps track of your heart rhythm. It may be able to spot occasionally abnormal heart rhythms that an ECG missed. Your doctor may want you to wear a Holter monitor for 1 to 2 days. Wires from electrodes on your chest go to a battery-operated recording device carried in your pocket or worn on a belt or shoulder strap.

  While wearing the monitor, you'll keep a diary of your activities and symptoms. Your doctor will compare the diary with the electrical recordings and try to figure out the cause of your symptoms.

• Event recorder. If you didn't have any irregular heart rhythms while you wore a Holter monitor, your doctor may recommend an event recorder, which can be worn for a longer time. There are several different types of event recorders. Event recorders are similar to Holter monitors and generally require you to push a button when you feel symptoms.
• Electrophysiology study (EP study). The doctor guides a flexible tube (catheter) through a blood vessel into your heart. More than one catheter is often used. Sensors on the tip of each catheter send signals and record your heart's electricity. Your doctor uses this information to identify the area that is causing your abnormal heartbeat.