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Tachycardia by Krisha McCoy, MS

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

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:

Medications

The following medications are used to treat this condition:

Beta-blockers (eg, atenolol, metoprolol, bisoprolol)
Calcium channel blockers (eg, diltiazem, verapamil)
Anti-arrhythmics, such as flecainide (Ambocor), procainamide (Procanbid), amiodarone (Cordarone), and sotalol (Betapace)

Ablation

Ablation is done during an electrophysiology study. Radiofrequency energy or cold energy is used to destroy the abnormality and possibly cure the problem.

Cardioverison

An electric shock is applied to the heart to stop the abnormal rhythm. This treatment may be done for life-threatening rhythms, such as ventricular tachycardia or ventricular fibrillation . It is also done for milder arrhythmias, such as atrial fibrillation .

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

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 )

RESOURCES:

American Heart Association http://www.americanheart.org
Heart Rhythm Society http://www.hrsonline.org/
National Heart, Lung, and Blood Institute http://www.nhlbi.nih.gov

CANADIAN RESOURCES:

Canadian Cardiovascular Society http://www.ccs.ca/home/index_e.aspx
Heart and Stroke Foundation of Canada http://www.heartandstroke.com/

References:

Arrhythmia prevention. Heart Rhythm Society website. Available at: http://www.hrspatients.org/patients/risk_factors/default.asp . Accessed April 19, 2007.
Implantable cardioverter defibrillator. American Academy of Family Physicians website. Available at: http://familydoctor.org/270.xml . Accessed April 19, 2007.
Paroxysmal atrial tachycardia (PAT). EBSCO DynaMed website. Available at: http://dynamed101.epnet.com/Detail.aspx?id=113613 . Accessed April 19, 2007.
Ventricular tachycardia. EBSCO DynaMed website. Available at: http://dynamed102.epnet.com/Detail.aspx?id=115268 . Accessed April 19, 2007.
What are arrhythmias? American Heart Association website. Available at: http://www.americanheart.org/presenter.jhtml?identifier=560 . Accessed April 19, 2007.

Last reviewed September 2012 by Michael J. Fucci, DO

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