Definition

Tachycardia is a rapid heart rate of more than 100 beats per minute. Sinus tachycardia, from the heart's sinus node, is a normal response to exercise, illness, or stress.

There are several types of abnormal tachycardias or arrhythmias. These can come from two places:

• Atria (the two smaller chambers on the top of the heart)—called supraventricular tachycardias
• Ventricles (the lower chambers of the heart)—called ventricular tachycardia

This condition can be life-threatening. But, it can be treated. If you think you or someone you know has this condition, get emergency help.

Electrical System and Chambers of the Heart

Copyright © Nucleus Medical Media, Inc.

Causes

This condition is caused by abnormal electrical impulses that control the heart.

Risk Factors

These factors increase your chance of having tachycardia. Tell your doctor if you have any of the following:

• Heart disease, especially a prior heart attack
• Cardiomyopathy —damage to the muscle wall of the lower chambers of the heart
• Electrolyte abnormalities—too much or too little calcium, sodium, magnesium, and potassium in the blood
• Myocardial ischemia—insufficient blood flow to heart muscle tissue
• Hypoxemia—not enough oxygen in the blood
• Acidosis—too much acid in the body’s fluids

Symptoms

If you have any of these symptoms do not assume it is due to this condition. These symptoms may be caused by other conditions. Tell your doctor if you have any of these:

• Heart palpitations
• Fast heart rate
• Dizziness
• Lightheadedness
• Fainting or near fainting
• Chest pain
• Shortness of breath

Diagnosis

• Your doctor will ask about your symptoms and medical history. You will also have an exam. Tests may include the following:
  • Electrocardiogram (ECG, EKG) —a test that records the heart’s activity by measuring electrical currents through the heart muscle
  • Holter monitor or event monitor —an ambulatory monitor to record your heart rhythm that can be worn from 1-30 days to detect arrhythmias and correlate symptoms with the heart rhythm
  • Exercise test —particularly if the symptoms occur during physical activity
  • Electrophysiology study —an invasive test where monitoring wires are placed inside the heart and the heart's conduction system is tested directly
  • Cardiac catheterization —a tube-like instrument inserted into the heart through a vein or artery (usually in the arm or leg) to detect problems with the heart and its blood supply

Treatment

Talk with your doctor about the best treatment plan for you. Treatment options include the following:

Implantable Cardioverter Defibrillator (ICD)

An ICD can be surgically placed into your body. This device monitors your heartbeat. It can apply a shock to correct an irregular heartbeat.

Device to Correct Tachycardia

Copyright © Nucleus Medical Media, Inc.

Prevention

Reducing risk of heart disease is the best way you can prevent this condition. Take the following steps:

• Maintain a healthy weight
• Begin a safe exercise program with the advice of your doctor
• If you smoke, quit
• Eat a healthful diet, one that is low in saturated fat and rich in whole grains, fruits, and vegetables
• Manage stress
• Avoid or limit the intake of caffeine and alcohol
• Have regular physical exams
• Treat underlying medical problems (eg, high blood pressure, cholesterol problems)