ArrhythmiasDefinition: An arrhythmia is any disorder of your heart rate or rhythm. It means your heart beats too fast, too slow, or with an irregular pattern. When the heart beats faster than normal, it is called tachycardia. When the heart beats too slow, it is called bradycardia.
Alternative Names: Dysrhythmias; Abnormal heart rhythms; Bradycardia; Tachycardia�
Causes, incidence, and risk factors: Normally, the 4 chambers of the heart (2 atria and 2 ventricles) contract in a very specific, coordinated manner. The electrical impulse that signals�your heart to contract in a synchronized manner begins in the sinoatrial node (SA node), which is�your heart's natural pacemaker. The signal leaves the SA node and travels through the 2 upper chambers (atria). Then the signal passes through another node (the AV node), and finally, through the lower chambers (ventricles). The result is that the chambers contract in a coordinated fashion. Problems can occur anywhere along this conduction system, causing various arrhythmias. Examples include: - Supraventricular tachycardia - a fast heart rate that originates in the upper chambers (atria). The most common are atrial fibrillation or flutter, and atrioventricular nodal reentry tachycardia.
- Ventricular tachycardia - a fast heart rate that originates in the�lower chambers (ventricles).
- Bradycardia�- a slow heart rate due to problems with the SA node's pacemaker ability, or�some interruption in conduction through the natural electrical pathways of the heart.
The�risks�of getting a tachycardia�or bradycardia varies greatly, depending on the condition of�your heart,�any history of a prior heart attack, blood chemistry imbalances, or endocrine abnormalities. Arrhythmias may also be caused by some substances or drugs. These include beta blockers, psychotropics, sympathomimetics, caffeine, amphetamines, and cocaine. Sometimes antiarrhythmic medications -- prescribed to treat one type of arrhythmia -- can actually cause another type of arrhythmia. Some types of arrhythmias may be life-threatening if not promptly and adequately treated.
Symptoms: The person may not have symptoms.
Signs and tests: A 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�appropriate to confirm or rule out suspected causes. EPS testing may be performed to locate the origin of the arrhythmia and determine the best treatment, especially if a pacemaker implantation or catheter ablation procedure is being considered.
Treatment: When an arrhythmia is serious, urgent�treatment may be required to restore a normal rhythm. This may include intravenous medications, electrical "shock" therapy (defibrillation or cardioversion), or implanting a temporary pacemaker to interrupt the arrhythmia. Supraventricular arrhythmias may be treated with anti-arrhythmic drugs. However, most supraventricular arrhythmias can be treated and cured with radiofrequency ablation, eliminating 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 terminate it, or a burst of pacing activity to override it. Bradycardias that cause symptoms can be treated by implanting a permanent pacemaker.
Expectations (prognosis): The outcome is dependent on several factors: - The kind of arrhythmia -- whether it is supraventricular tachycardia, or a more dangerous arrhythmia such as ventricular tachycardia or ventricular fibrillation, which are potentially fatal
- The overall pumping ability of the heart
- The underlying disease and its ability to be treated
With bradycardias that are treated with a permanent pacemaker, there is usually a good outlook.
Calling your health care provider: Call your provider if you develop any of the symptoms of a possible arrhythmia. Also call your provider if you have already been diagnosed with an arrhythmia, and your symptoms worsen or do not improve with treatment.
Prevention: Taking steps to prevent coronary artery disease may reduce�your chance�of developing an arrhythmia. These steps include not smoking, eating a well-balanced, low-fat diet, and exercising regularly.
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