Atrial flutter

Atrial flutter (AFL) is a common abnormal heart rhythm that starts in the atrial chambers of the heart. When it first occurs, it is usually associated with a fast heart rate and is classified as a type of supraventricular tachycardia. Atrial flutter is characterized by a sudden-onset (usually) regular abnormal heart rhythm on an electrocardiogram (ECG) in which the heart rate is fast. Symptoms may include a feeling of the heart beating too fast, too hard, or skipping beats, chest discomfort, difficulty breathing, a feeling as if one's stomach has dropped, a feeling of being light-headed, or loss of consciousness. Atrial flutter (AFL) is a common abnormal heart rhythm that starts in the atrial chambers of the heart. When it first occurs, it is usually associated with a fast heart rate and is classified as a type of supraventricular tachycardia. Atrial flutter is characterized by a sudden-onset (usually) regular abnormal heart rhythm on an electrocardiogram (ECG) in which the heart rate is fast. Symptoms may include a feeling of the heart beating too fast, too hard, or skipping beats, chest discomfort, difficulty breathing, a feeling as if one's stomach has dropped, a feeling of being light-headed, or loss of consciousness. Although this abnormal heart rhythm typically occurs in individuals with cardiovascular disease (e.g. high blood pressure, coronary artery disease, and cardiomyopathy) and diabetes mellitus, it may occur spontaneously in people with otherwise normal hearts. It is typically not a stable rhythm, and often degenerates into atrial fibrillation (AF). However, it does rarely persist for months to years. Similar to the abnormal heart rhythm atrial fibrillation, atrial flutter also leads to poor contraction of the atrial chambers of the heart. This leads to pooling of the blood in the heart and can lead to the formation of blood clots in the heart which pose a significant risk of breaking off and traveling through the bloodstream resulting in strokes. A supraventricular tachycardia with a ventricular heart rate of 150 beats per minute is suggestive (though not necessarily diagnostic) of atrial flutter. Administration of adenosine in the vein (intravenously) can help medical personnel differentiate between atrial flutter and other forms of supraventricular tachycardia. Immediate treatment of atrial flutter centers on slowing the heart rate with medications such as beta blockers (e.g., metoprolol) or calcium channel blockers (e.g., diltiazem) if the affected person is not having chest pain, has not lost consciousness, and if their blood pressure is normal (known as stable atrial flutter). If the affected person is having chest pain, has lost consciousness, or has low blood pressure (unstable atrial flutter), then an urgent electrical shock to the heart to restore a normal heart rhythm is necessary. Long-term use of blood thinners (e.g., warfarin or apixaban) is an important component of treatment to reduce the risk of blood clot formation in the heart and resultant strokes. Medications used to restore a normal heart rhythm (antiarrhythmics) such as ibutilide effectively control atrial flutter about 80% of the time when they are started but atrial flutter recurs at a high rate (70–90% of the time) despite continued use. Atrial flutter can be treated more definitively with a technique known as catheter ablation. This involves the insertion of a catheter through a vein in the groin which is followed up to the heart and is used to identify and interrupt the electrical circuit causing the atrial flutter (by creating a small burn and scar). Atrial flutter was first identified as an independent medical condition in 1920 by the British physician Sir Thomas Lewis (1881–1945) and colleagues. AFL is the second most common pathologic supraventricular tachycardia but occurs at a rate less than one-tenth of the most common supraventricular tachycardia (atrial fibrillation). The overall incidence of AFL has been estimated at 88 cases per 100,000 person-years. The incidence of AFL is significantly lower (~5 cases/100,000 person-years) in those younger than age 50 and is far more common (587 cases/100,000 person-years) in those over 80 years of age. While atrial flutter can sometimes go unnoticed, its onset is often marked by characteristic sensations of the heart feeling like it is beating too fast or hard. Such sensations usually last until the episode resolves, or until the heart rate is controlled. Atrial flutter is usually well tolerated initially (a high heart rate is for most people just a normal response to exercise), however, people with other underlying heart disease (such as coronary artery disease) or poor exercise tolerance may rapidly develop symptoms, such as shortness of breath, chest pain, lightheadedness or dizziness, nausea and, in some patients, nervousness and feelings of impending doom. Prolonged atrial flutter with fast heart rates may lead to decompensation with loss of normal heart function (heart failure). This may manifest as exercise intolerance (exertional breathlessness), difficulty breathing at night, or swelling of the legs and/or abdomen. Although often regarded as a relatively benign heart rhythm problem, atrial flutter shares the same complications as the related condition atrial fibrillation. There is paucity of published data directly comparing the two, but overall mortality in these conditions appears to be very similar. Rapid heart rates may produce significant symptoms in patients with pre-existing heart disease and can lead to inadequate blood flow to the heart muscle and even a heart attack. In rare situations, atrial flutter associated with a fast heart rate persists for an extended period of time without being corrected to a normal heart rhythm and leads to a tachycardia-induced cardiomyopathy. Even in individuals with a normal heart, if the heart beats too quickly for a prolonged period of time, this can lead to ventricular decompensation and heart failure.