Arrhythmias Tests

What tests can be done?

First the doctor will take a medical history and do a thorough physical exam. Then one or more tests may be used to check for an arrhythmia and to decide whether it is caused by heart disease. Sometimes an arrhythmia can be detected by listening to the heart with a stethoscope. To identify an arrhythmia, the heart's activity must be recorded on an electrocardiogram (ECG or EKG).

An arrhythmia may not occur at the time of the exam even though symptoms are present at other times. In such cases, tests will be done if necessary to find out whether an arrhythmia is causing the symptoms.

Tests for Detecting Arrhythmias

Electrocardiogram (ECG or EKG). Records the electrical activity of the heart. Each time the heart beats, it sends out an electric-like signal. An ECG machine can record this activity. To record the ECG, small patches or stickers called electrodes are placed on different parts of the body. One is put on each arm and leg and six across the chest.

With various combinations of these electrodes, different tracings of the heart's electrical activity can be made and permanently recorded on paper or in a computer. The types of ECGs are:

Resting ECG. The patient lies down for a few minutes while a record is made. In this type of ECG, disks are attached to the patient's arms and legs as well as to the chest. Records about 12 seconds of heart electrical activity.

Exercise ECG (stress test). The patient exercises either on a treadmill machine or bicycle while connected to the ECG machine. This test tells whether exercise causes arrhythmias or makes them worse or whether there is evidence of inadequate blood flow to the heart muscle ("ischemia"). Records electrical activity for duration of exercise (10 to 20 minutes).

24-hour ECG (Holter) monitoring. The patient goes about his or her usual daily activities while wearing a small, portable recorder that connects to the disks on the patient's chest. Over time, this test shows changes in rhythm (or "ischemia") that may not be detected during a resting or exercise ECG. Can record continuously for 24 to 48 hours.

Transtelephonic monitoring. The patient wears the recorder and disks over a period of a few days to several weeks. When the patient feels an arrhythmia, he or she telephones a monitoring station where the record is made. If access to a telephone is not possible, the patient has the option of activating the monitor's memory function. Later, when a telephone is accessible, the patient can transmit the recorded information from the memory to the monitoring station. Transtelephonic monitoring can reveal arrhythmias that occur only once every few days or weeks.

Electrophysiologic studies (EPS)

Intracardiac Electrophysiologic Procedure. Sometimes it's necessary to study the heart's electrical system with an intracardiac (within the heart) electrophysiologic procedure. In this, one or more long, thin tubes (catheters) are placed into the large blood vessels in the legs, arms or both. Then the tips of the catheters are moved into the heart. Once in the heart, the catheters can record electrical signals from the normal electrical system. This gives much more precise information than an ordinary ECG. During these studies, the heart can be stimulated to beat rapidly or irregularly. The heart's response to this - and the way electricity moves around the heart during a tachycardia - helps the cardiologist diagnose the nature of an arrhythmia. Sometimes abnormal tissue causing an arrhythmia is then destroyed by heating it with a probe (called radioablation therapy).

Esophageal Electrophysiologic Procedure. In some situations, your cardiologist may recommend that an esophageal electrophysiologic procedure be done. This is used to diagnose or treat the type of tachycardia you have. In this procedure, a thin, soft, flexible plastic tube is inserted into your nostril and positioned in the esophagus. (The esophagus is the tube that connects the mouth and stomach.) Since the esophagus is close to the upper chambers (atria) of the heart, an ECG recording there gives more precise information than a regular ECG. An electrical stimulator may be used to make the heart beat faster to try to restart your arrhythmia. This helps your doctor make the right diagnosis.

During this procedure certain medications may be tested to find the one that will be most effective. The esophageal electrophysiologic procedure also may be performed to temporarily stop certain types of arrhythmias. This procedure is similar, but less invasive than an intracardiac procedure. Ablation therapy (directly destroying abnormal heart conduction tissue) cannot be performed with the esophageal procedure.