Your Health - Arrhythmias

Arrhythmias

by Rosalyn Carson-DeWitt, MD

Definition

Arrhythmias are abnormal beats of the heart. Types of arrhythmias include:

Heartbeats that are too slow ( bradycardia )
Heartbeats that are too fast ( tachycardia )
Extra beats
Skipped beats
Beats coming from abnormal areas of the heart

Causes

An arrhythmia can be caused by:

The heart's natural pacemaker (SA node) developing an abnormal rate or rhythm
The normal conduction pathway being interrupted
Another part of the heart taking over as pacemaker

Conduction Pathways of the Heart

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors include:

Excess caffeine
Stress
Tobacco use
Alcohol use
Certain diet pills or decongestants
Cocaine
Certain antidepressant medications
Digitalis overdose
Endocrine disorders, such as thyroid or adrenal gland problems
Anemia
High blood pressure
Coronary artery disease
Problems with heart valves
Heart muscle damage after heart attack
Rheumatic heart disease
Cardiomyopathy
Diabetes
Liver disease
Typhoid fever
Hypothermia
Electric shock or lightening strike
Complication after near-drowning

Symptoms

Some arrhythmias may occur without any symptoms. Others may cause noticeable symptoms, such as:

Fainting
Dizziness, sensation of light-headedness
Sensation of your heart fluttering (palpitations)
Sensation of a missed or extra heart beat
Weakness
Fatigue
Shortness of breath
Chest pain

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. In particular, the doctor will listen to your heart with a stethoscope.

Tests may include:

Blood tests—to look for certain markers in the blood that help the doctor determine what is happening with your heart
Urine tests—to look for certain markers in the urine that help the doctor determine what is happening with your heart
Electrocardiogram (EKG) —records the heart's activity by measuring electrical currents through the heart muscle
Echocardiogram —uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
24-hour holter monitor—a portable EKG that you wear as you perform normal daily activities
Exercise stress test —records the heart's electrical activity during increased physical activity. For patients who cannot exercise, an intravenous medication may be given to simulate the effects of physical exertion on the heart.
Nuclear scanning—Radioactive material is injected into a vein and observed as it is absorbed by the heart muscle. Areas with diminished flow, and therefore uptake of the radioactive material, show up as dark spots on the scan.
Coronary angiography —x-rays taken after a dye is injected into the coronary arteries—allows the doctor to look for abnormalities (narrowing, blockage) in the arteries and evaluate the function of the heart.
Electrophysiological study—In this study, a series of electrodes is threaded through your blood vessels and attached to various spots in your heart. This allows doctors to see how electric impulses travel through the heart, aiding in the diagnosis of problems with conduction and/or identification of tissues that may be causing the arrhythmia.
Tilt table testing—This test is usually recommended for patients with history of fainting. First, you lie flat on a table that is later tilted into a vertical position. Your heart rate and blood pressure as well as other parameters are closely monitored during the tilting.

Treatment

Treatment may include:

Antiarrhythmic Medications

These will help slow down or speed up your heart rate, or return your heart rhythm to normal (cardioversion), depending on your need.

Electrical Cardioversion or Defibrillation

These treatments involve placing paddles on the chest or back. An electrical current is passed through the chest wall to the heart to reset its electrical circuits, and attempt to return the heart rhythm to normal.

Automatic Implantable Defibrillator

A tiny defibrillator can be surgically implanted in your chest to monitor your heart rhythm. If a dangerous arrhythmia is detected, the device automatically shocks the heart in an attempt to return the heart rhythm to normal.

Artificial Pacemaker

The pacemaker is surgically implanted in your chest. It takes over the job of providing the electrical impulses needed for establishing an appropriate heart rhythm.

Ablation Therapy

An area of the heart that is responsible for an abnormal rhythm may be surgically removed or altered (ablated) with various techniques (eg, cryoablation ) to prevent it from generating an arrhythmia.

If you are diagnosed with an arrhythmia, follow your doctor's instructions .

Prevention

To help prevent arrhythmias:

Treat underlying conditions that might lead to arrhythmias.
Avoid substances that might trigger or worsen an arrhythmia, including:
- Caffeinated beverages
- Alcohol
- Tobacco
- Certain medications
Follow general advice for preventing the development of heart disease, including:
- Maintain an appropriate weight.
- Consult your doctor about a safe exercise program.
- Do not smoke. If you smoke, quit .
- Eat a healthful diet, one that is low in saturated fat and rich in whole grains, fruits, and vegetables.
- Appropriately treat your high blood pressure and/or diabetes.
- Ask your doctor if you should take cholesterol-lowering medications.

RESOURCES:

American Heart Association
http://www.americanheart.org/

Texas Heart Institute
http://www.texasheartinstitute.org/

CANADIAN RESOURCES:

Canadian Cardiovascular Society
http://www.ccs.ca/home/index_e.aspx/

Canadian Family Physician
http://www.cfp.ca/

References:

Arrhythmias. American Heart Association website. Available at: http://www.americanheart.org/presenter.jhtml?identifier=10845 . Accessed July 7, 2009.

Braunwald E, Zipes DP, Libby P, et al. Heart Disease: A Textbook of Cardiovascular Medicine . 6th ed. Philadelphia, PA: WB Saunders Company; 2001.

National Heart, Lung, and Blood Institute website. Available at: http://www.nhlbi.nih.gov/ . Accessed July 7, 2009.

Tracy CM, Akhtar M, DiMarco JP, et al. American College of Cardiology/American Heart Association clinical competence statement on invasive electrophysiology studies, catheter ablation, and cardioversion: A report of the American College of Cardiology/American Heart Association/American College of Physicians-American Society of Internal Medicine task force on clinical competence. Circulation. 2000;102:2309.

Weber BE, Kapoor WN. Evaluation and outcomes of patients with palpitations. Am J Med. 1996;100:138.

Last reviewed September 2009 by David N. Smith, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.