Arrhythmias (or dysrhythmias) are abnormal rhythms of the heart which cause the heart to pump less effectively.
Normally, as the electrical impulse moves through the heart, the heart contracts – about 60 to 100 times a minute. Each contraction represents one heartbeat. The atria contract a fraction of a second before the ventricles so their blood empties into the ventricles before the ventricles contract.
Under some conditions almost all heart tissue is capable of starting a heartbeat, or becoming the pacemaker. An arrhythmia occurs when:
According to the latest recommendations from the American College of Physicians and the American Academy of Family Physicians, for most patients with atrial fibrillation, slowing heart rate with atenolol, metoprolol, diltiazem, or verapamil is the most appropriate treatment. Patients with atrial fibrillation should receive blood thinners to prevent stroke unless they have a condition that would make anticoagulation dangerous (such as alcoholism with frequent falls).
Patients who choose conversion to normal heart rhythm instead of rate control because of symptoms can select electrical or medical cardioversion. For patients who choose cardioversion, outcomes are similar whether patients have immediate cardioversion following a special test (transesophageal echocardiogram) to make sure no blood clots exist in the atria or if they delay cardioversion until blood thinners take effect. Most patients take medications to maintain normal rhythm after cardioversion.