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.
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. .
Symptoms vary depending on the type of arrhythmia, but may include: dizziness, or light-headednesspalpitations, or an unusual awareness of the heart beating in the chestshortness of breathfatigueweaknesschest painfainting
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 heartdisease of the heart valves, including infections known as endocarditisdisease of the tissue that surrounds the heart, such as bacterial pericarditiscongestive 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 heartchemicals such as adrenaline, alcohol, or caffeinecertain prescription medications, including tricyclic antidepressants, such as amitriptyline and nortriptylinecertain 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.
A person can reduce the risk for developing arrhythmias by: not smokingcontrolling high blood pressurecontrolling blood cholesterolcontrolling diabetesexercising regularlylimiting the intake of alcohol and caffeineeating a diet designed to minimize heart disease
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.
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.
Arrhythmias are not contagious and pose no risk to others.
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.
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.
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.
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.