Tachycardia

Diagnosis

In diagnosing tachycardia, the patient may be asked about or tested for conditions that may trigger the fibrillation, such as heart disease or a thyroid problem. The patient may have two heart monitoring tests: active and passive.

Active Tests

These tests try to induce an irregular heartbeat while the patient is monitored closely. They include:

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. The Mayo specialists have over 25 years of experience in treating patients who have various heart arrhythmias.

In the EP test, catheters (thin, flexible tubes) with electrodes at the tips are threaded through the patient's blood vessels to various spots within the heart. Once in place, the electrodes can precisely map the spread of electrical impulses through the heart. During the test, the electrophysiologist (a cardiologist who specializes in heart rhythms) may use the electrodes to stimulate the heart to beat at rates that may trigger — or halt — an irregular heartbeat. This allows the doctor 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 catheter-based treatment option for many arrhythmias — is determined by the doctor to be appropriate treatment, the procedure can be performed during EP testing. Read more about catheter radiofrequency ablation.

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). The test may use a drug to stimulate the heart similar to stimulation by exercise. This may be particularly helpful to patients who have difficulty exercising. The stress test can also be used to detect coronary artery disease.

Passive Tests

These tests involve monitoring the heart during regular activity. They include:

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.

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 during the daily routine.

Echocardiogram (Doppler Echocardiogram)

This test uses sound waves to produce detailed images of the patient's heart. Through a handheld device (transducer) 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.

Blood Tests

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

The comprehensive diagnosis is critical in determining the best treatment for the patient.