Tachycardia

Diagnosis

A comprehensive diagnosis at Mayo Clinic helps determine the severity of the tachycardia and the most appropriate treatment. At Mayo Clinic, electrophysiologists (cardiologists with specialized training in the diagnosis and treatment of heart rhythm disorders) work with a team of medical specialists to accurately diagnose tachycardia.

In diagnosing tachycardia, the patient may be asked about the presence of or tested for conditions that may trigger tachycardia, such as heart disease or a thyroid problem. At Mayo Clinic, several tests may be given in the clinic to determine the severity of the tachycardia.

Electrophysiology (EP) Testing and Mapping
Mayo Clinic is an international leader in catheter ablation and implantable devices and uses the most advanced technology to treat arrhythmias including tachycardias. At each of its locations, Mayo Clinic has experienced electrophysiologists who perform testing. Mayo Clinic is nationally recognized for its experience, research and innovations in electrophysiology assessments and its 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 to several areas within the heart. Once in place, the electrodes can precisely map the spread of electrical impulses through the heart. 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. This allows the physician to observe the location of the arrhythmia and the mechanics of the heart that may be causing the irregular heartbeat.

The ability to trigger and then stop a tachycardia may also be used to test various treatment methods for their effectiveness. For example, if catheter radiofrequency ablation (a minimally-invasive procedure that uses catheters to reach the heart and destroy abnormal heart tissue) is determined by the doctor to be 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)
This test uses sound waves to produce detailed images of the patient's heart. Through a handheld device (transducer) placed on the patient's chest, sound waves bounce off the heart and are reflected 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.

Coronary Angiogram
During coronary angiography, a type of dye that's visible on an X-ray is injected into the blood vessels of the heart. The X-ray machine takes a series of images, which provide a detailed look inside the blood vessels to determine if coronary artery disease is causing a tachycardia.

Blood Tests
Blood tests help identify thyroid problems or other blood chemistry abnormalities that may lead to tachycardia.

Stress Test
Tachycardia may be triggered or worsen when the patient is exercising. During a stress test, the patient may exercise on a treadmill or stationary bicycle, with close monitoring of heart activity by an electrocardiogram (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 the heart's electrical activity.

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 and the electrodes (sticky pads with wires) applied by the patient on her or his chest. When the patient feels symptoms, a push of a button begins the ECG recording. For select patients, an implanted recorder may be used.