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.
On the other hand, the beat may be irregular either because it begins in the wrong part of the heart, or because part of the heart is diseased and does not conduct the electrical impulse properly. .
What are the causes and risks of the condition?
Most arrhythmias are caused by heart disease
- 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 (main pumping) chambers.
What can be done to prevent the condition?
A person can reduce the risk for developing arrhythmias by:
- not smoking
- controlling high blood pressure
- controlling blood cholesterol
- controlling diabetes
- exercising regularly
- limiting the intake of alcohol and caffeine
- eating a diet designed to minimize heart disease
How is the condition diagnosed?
Arrhythmias can be detected by an electrocardiogram (ECG), which shows the pattern of electrical activity within the heart muscle. A device called a Holter monitor can also be used. This device records all heartbeats within a 24-hour period.
More complicated arrhythmias can be identified by a cardiac catheterization. In this procedure, a doctor inserts a catheter into the heart through a vein in the leg. The electrical impulses of the heart can then be measured to determine exactly what type of arrhythmia is present.
Long Term Effects
What are the long-term effects of the condition?
Untreated arrhythmias can cause heart attacks or strokes. If the heart rhythm becomes so disordered that the heart can no longer pump, the person dies unless he or she can be resuscitated immediately.
What are the risks to others?
Arrhythmias are not contagious and pose no risk to others.
What are the treatments for the condition?
Different treatments are available, depending on the type of arrhythmia being treated. Medications such as amiodarone (i.e., Cardarone, Pacerone), procainamide (i.e., Procanbid, Pronestyl)), and propranolol (i.e., Inderal, InnoPran) can be used to control the rate or restore the rhythm of the heart. Calcium channel blockers, such as verapamil (i.e., Calan, Covera, Isoptin, Verelan), have been used for over 20 years.
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.
How is the condition monitored?
A person with an arrhythmia needs to make regular visits to the healthcare provider. The provider will monitor the effectiveness of medications, and evaluate the need for a pacemaker. Any new or worsening symptoms should be reported to the healthcare provider.