Arrhythmia

Diagnosis

A comprehensive diagnosis at Mayo Clinic helps determine the severity of the arrhythmia and the most appropriate treatment. At Mayo Clinic, electrophysiologists (cardiologists with expertise in the diagnosis and treatment of heart rhythm disorders) lead a team of medical specialists in testing to diagnose arrhythmia.

To arrive at a diagnosis, the physician may ask the patient about the presence of conditions that may trigger heart arrhythmia, such as heart disease or a problem with the thyroid gland, or conduct tests for those conditions.

Electrophysiology (EP) Testing and Mapping
Mayo Clinic is a national leader in electrophysiology, the medical specialty of heart rhythms. At each of its locations, Mayo Clinic has experienced electrophysiologists (cardiologists with specialized training in the diagnosis and treatment of heart rhythm disorders). Mayo Clinic is nationally recognized for its experience, research and innovations in electrophysiology assessments, and use of advanced equipment for recording and analyzing heart rhythms.

In electrophysiology testing, catheters (thin, flexible tubes) with electrodes at the tips are threaded through the patient's blood vessels at several places within the heart. Once in place, the electrodes can precisely map the spread of electrical impulses throughout the organ. During the test, the electrophysiologist may use the electrodes to stimulate the heart to beat at rates that may trigger, or halt, an irregular heartbeat. The physician can observe the location of the arrhythmia and the mechanics of the heart that may be causing the irregular heartbeat.

Triggering and then stopping an arrhythmia may also be applied to test various treatment methods for their effectiveness. For example, if the physician determines that catheter radiofrequency ablation (a minimally-invasive procedure that uses catheters to reach the heart and destroy abnormal heart tissue) is the appropriate treatment, the procedure can be performed during EP testing. Read more about catheter radiofrequency ablation.

Electrocardiogram (ECG)
Electrodes (sensor patches with wires attached) are placed on the patient's skin to measure the electrical impulses given off by the heart. The ECG measures the timing and duration of each electrical phase in the heartbeat.

Echocardiogram (Doppler Echocardiogram)
Sound waves produce detailed images of the patient's heart. From a hand-held device (transducer) placed on the chest, sound waves are bounced off the heart and reflected back to produce video images of the heart's size, structure and motion. The echocardiogram can also be used to measure the heart's blood volume and the speed and direction of blood flow through the heart.

Transesophageal Echocardiogram
A tube with a transducer (sound device) is inserted down the esophagus, which runs from the throat to the stomach. Because the esophagus lies close to the heart, the proximity of the transducer provides an even more detailed image of the heart's size, structure and motion.

Stress Test
Some arrhythmias are triggered by exercise or worsen during exercise. During a stress test, the person exercises on a treadmill or stationary bicycle while heart activity is closely monitored on an electrocardiograph (ECG). If patients have difficulty exercising, a drug may be given to stimulate the heart into mimicking its activity during exercise. The stress test can also be used to detect coronary artery disease.

Some tests involve monitoring the heart during activity:

Holter Monitor
A Holter monitor is a portable ECG device that the patient wears for a day or more to record heart rate and rhythm during the patient's daily routine.

Event Monitor
For irregular heartbeats that occur sporadically, this portable ECG device is kept at home so the patient can attach it and activate the ECG recording when experiencing symptoms of an arrhythmia. The device is small, about the size of a portable compact disc player, and can be clipped on to clothing. Patients can apply the electrodes (sticky pads with wires) onto their chest. When the patient feels symptoms, a push of a button begins the ECG recording. For select patients, an implanted recorder may be used.