What is Arrhythmia - Abnormal Heartbeat?
Written by Kimberly Vaughn, MD
Monday, 05 October 2009
An arrhythmia of the heart is an abnormality of the rhythm or rate of the heartbeat. The arrhythmia is caused by a disturbance of the normal electrical activity within the heart.
What is going on in the body?
Arrhythmias can be divided into 2 main groups: tachycardias and bradycardias. Tachycardias cause a rapid heartbeat, with over 100 beats per minute. Bradycardias cause a slow heartbeat, with less than 60 beats per minute. The rhythm of the heart may be regular during an arrhythmia. In other words, each beat of the atria, or upper chambers of the heart, is followed by one beat of the ventricles, or lower chambers of the heart. The beat may also be irregular and may begin in an abnormal area of the heart.
What are the causes and risks of the condition?
Most arrhythmias are caused by heart disease, including:
- coronary artery disease, a condition in which atherosclerosis, or narrowing of the arteries, decreases the blood flow to the heart
- disease of the heart valves, including infections known as endocarditis
- disease of the tissue that surrounds the heart, such as bacterial pericarditis
- congestive heart failure, a disorder in which a weakened heart fails to pump enough blood to body organs
Arrhythmias may also be caused by:
- disease in the electrical system of the heart
- chemicals such as adrenaline, alcohol, or caffeine
- certain prescription medications, including tricyclic antidepressants, such as amitriptyline and nortriptyline
- certain over-the-counter medications, such as pseudoephedrine
Arrhythmias may or may not be life threatening. In general, arrhythmias that begin in the upper part of the heart are less dangerous than those that begin in the lower chambers.
What are the treatments for the condition?
Different treatments are available, depending on the type of arrhythmia being treated. Medications such as amiodarone, procainamide, and propranolol can be used to control the rate or restore the rhythm of the heart.
Calcium channel blockers, such as verapamil, have been used over 20 years. However, findings of two recent studies show that people who take a calcium channel blocker have a much higher incidence of complications than people taking other medications for heart disease. One study, for example, found that the risk of heart attack was 27% greater, and the risk of congestive heart failure was 26% higher. The American Heart Association recommends that individuals discuss risks and benefits of the medication with the healthcare provider.
A pacemaker may be inserted to control an arrhythmia or speed up a heart that is beating too slowly. Certain types of implantable pacemakers called cardiac defibrillators can sense a life-threatening arrhythmia and send an electrical shock to the heart. Often a person's life can be saved this way without a trip to the hospital.
What are the side effects of the treatments?
The side effects of treatment for arrhythmias vary according to the medications used, but include allergic reactions. Calcium channel blockers can cause swelling of the legs, as well as a higher risk of heart attack and congestive heart failure.
Implanting a pacemaker is a minor surgical procedure, with some risk of infection, bleeding, and allergic reaction to the anesthesia.
What happens after treatment for the condition?
Unless a severe or life-threatening arrhythmia is present, a person can generally resume normal activities once treatment is successful. Most individuals with a treated arrhythmia are encouraged to begin a regular exercise program. The person should make every effort to reduce coronary risk factors. This may include smoking cessation, control of other diseases such as diabetes and high blood pressure, and eating a healthy diet to minimize heart disease. Medications may need to be adjusted to achieve the best response.