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Alternative Names Return to topDysrhythmias; Abnormal heart rhythms; Bradycardia; Tachycardia
Definition Return to top
An arrhythmia is a disorder of the heart rate (pulse) or heart rhythm, such as beating too fast (tachycardia), too slow (bradycardia), or irregularly.
Causes Return to top
Normally, the four chambers of the heart (two atria and two ventricles) contract in a very specific, coordinated way.
The electrical impulse that signals your heart to contract in a synchronized manner begins in the sinoatrial node (SA node). This is your heart's natural pacemaker.
The signal leaves the SA node and travels through the two upper chambers (atria). Then the signal passes through another node (the AV node). Finally, it passes through the lower chambers (ventricles). This path enables the chambers to contract in a coordinated fashion.
Problems can occur anywhere along this conduction system, causing various arrhythmias. Examples include:
The risk of getting a tachycardia or bradycardia varies greatly, depending on:
Arrhythmias may also be caused by some substances or drugs, including:
Sometimes anti-arrhythmic medications -- prescribed to treat one type of arrhythmia -- can actually cause another type of arrhythmia.
Symptoms Return to top
You may not have symptoms.
Exams and Tests Return to top
The doctor will listen to your heart with a stethoscope and feel your pulse. Your blood pressure may be low or normal.
The following tests may be performed to identify arrhythmias:
If an arrhythmia is detected, various tests may be done to confirm or rule out suspected causes. EPS testing may be done to find the arrhythmia and determine the best treatment, especially if a pacemaker or catheter ablation procedure is being considered.
Treatment Return to top
When an arrhythmia is serious, urgent treatment may be required to restore a normal rhythm. This may include:
Supraventricular arrhythmias may be treated with:
Many supraventricular arrhythmias can be treated and cured with radiofrequency ablation. This avoids the need for lifelong drug therapy.
Increasingly, most ventricular tachycardias are treated with an implantable cardioverter-defibrillator (ICD). As soon as arrhythmia begins, the ICD sends a shock to stop it, or a burst of pacing activity to override it.
Bradycardias that cause symptoms can be treated by implanting a permanent pacemaker.
Outlook (Prognosis) Return to top
The outcome depends on several factors:
Some types of arrhythmias may be life-threatening if not promptly and properly treated.
With bradycardias treated with a permanent pacemaker, the outlook is usually good.
Possible Complications Return to top
When to Contact a Medical Professional Return to top
Call your health care provider if:
Prevention Return to top
Taking steps to prevent coronary artery disease may reduce your chance of developing an arrhythmia. These steps include: