Atrial flutter is an abnormal heart rhythm that occurs in the atria of the heart. The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The International Statistical Classification of Diseases and Related Health Problems 10th Revision ( ICD -10) is a coding of diseases and signs symptoms abnormal findings I00-I99 - Diseases of the Circulatory system (I00-I02 Acute rheumatic fever ( Rheumatic fever without mention of Heart The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. The Diseases Database is a free Website that provides information about the relationships between medical conditions Symptoms, and Medications. MedlinePlus, with the MedlinePlus Medical Encyclopedia, is a website network containing Health information from the world's largest medical Library eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely two medical doctors Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Dysrhythmia redirects here For the American band see Dysrhythmia (band. In Anatomy, the atrium (plural atria) refers to a chamber or space The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic When it first occurs, it is usually associated with a fast heart rate or tachycardia, and falls into the category of supra-ventricular tachycardias. A supraventricular tachycardia ( SVT) is a rapid rhythm of the Heart in which the origin of the electrical signal is either the atria or While this rhythm occurs most often in individuals with cardiovascular disease (eg: hypertension, coronary artery disease, and cardiomyopathy), it may occur spontaneously in people with otherwise normal hearts. Hypertension, also referred to as high blood pressure, HTN or HPN, is a medical condition in which the Blood pressure is chronically elevated Coronary artery disease (CAD (or atherosclerotic Heart disease) is the end result of the accumulation of atheromatous plaques within the walls Cardiomyopathy, which literally means "heart muscle disease" is the deterioration of the function of the Myocardium (i It is typically not a stable rhythm, and frequently degenerates into atrial fibrillation. Atrial fibrillation ( AF or afib) is a Cardiac arrhythmia (abnormal heart rhythm that involves the two upper chambers ( atria) of the Heart However, it does rarely persist for months to years.

Atrial flutter was first identified as an independent medical condition in 1920 by the British physician Sir Thomas Lewis (1882-1945) and colleagues. Sir Thomas Lewis, CBE, FRS ( 26 December 1881, Cardiff, Wales &ndash 17 March 1945, Rickmansworth ^[1]

Signs and symptoms

While atrial flutter can sometimes go unnoticed, its onset is often marked by characteristic sensations of regular palpitations. A palpitation (medical term ectopic heart beat) is an abnormal awareness of the beating of the Heart, whether it is too slow too fast irregular 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 or poor exercise tolerance may rapidly develop symptoms, which can include shortness of breath, chest pains, lightheadedness or dizziness, nausea and, in some patients, nervousness and feelings of impending doom.

Prolonged fast flutter may lead to decompensation with loss of normal heart function (heart failure). Heart failure is a Cardiac condition that occurs when a problem with the structure or function of the Heart impairs its ability to supply This may manifest as effort intolerance (exertional breathlessness), nocturnal breathlessness, or swelling of the legs or abdomen.

Pathophysiology

Atrial flutter is caused by a reentrant rhythm in either the right or left atrium. Dysrhythmia redirects here For the American band see Dysrhythmia (band. Typically initiated by a premature electrical impulse arising in the atria, atrial flutter is propagated due to differences in refractory periods of atrial tissue. This creates a self perpetuating loop of electrical activity moving around the atrium.

The impact and symptoms of atrial flutter depend on the heart rate of the patient. Heart rate is a measure of the ventricular rather than atrial activity. Impulses from the atria are conducted to the ventricles through the atrio-ventricular node. The atrioventricular node (abbreviated AV node) is an area of specialized tissue between the atria and the ventricles of the Heart, specifically Due primarily to its longer refractory period, the AV node exerts a protective effect on heart rate by blocking atrial impulses in excess of about 180 beats/minute (This block is dependent on the age of the patient, and can be calculated roughly by subtracting patient age from 220). If the flutter rate is 300/minute only half of these impulses will be conducted, giving a ventricular rate of 150/minute, or a 2:1 heart block. A heart block is a disease in the electrical system of the Heart. The addition of rate-controlling drugs or conduction system disease can increase this block substantially (see image below).

Classification

There are two types of atrial flutter, the common type I and rarer type II. ^[2] Most individuals with atrial flutter will manifest only one of these. Rarely someone may manifest both types; however, they can only manifest one type at a time.

Type I atrial flutter, counterclockwise rotation with 4:1 AV nodal block. The atrioventricular node (abbreviated AV node) is an area of specialized tissue between the atria and the ventricles of the Heart, specifically

Type I atrial flutter, also known as common atrial flutter or typical atrial flutter, has an atrial rate of 240 to 350 beats/minute. However, this rate may be slowed by antiarrhythmic agents. Antiarrhythmic agents are a group of Pharmaceuticals that are used to suppress fast rhythms of the Heart ( Cardiac arrhythmias) such as Atrial fibrillation

The reentrant loop circles the right atrium, passing through the isthmus - a body of fibrous tissue in the lower atrium between the inferior vena cava, and the tricuspid valve. Type I flutter is further divided into two subtypes, known as counterclockwise atrial flutter and clockwise atrial flutter depending on the direction of current passing through the loop. Counterclockwise atrial flutter (known as cephalad-directed atrial flutter) is more commonly seen. The flutter waves in this rhythm are inverted in ecg leads II, III, and aVF. The re-entry loop cycles in the opposite direction in clockwise atrial flutter, thus the flutter waves are upright in II, III, and aVF.

Catheter ablation of the isthmus is a procedure usually available in the electrophysiology laboratory. Eliminating conduction through the isthmus prevents reentry, and if successful, prevents the recurrence of the atrial flutter.

Type II flutter follows a significantly different re-entry pathway to type I flutter, and is typically faster, usually 340–430 beats/minute.

Complications

Although often regarded as a relatively benign rhythm problem, atrial flutter shares the same complications as the related condition atrial fibrillation. Atrial fibrillation ( AF or afib) is a Cardiac arrhythmia (abnormal heart rhythm that involves the two upper chambers ( atria) of the Heart There is paucity of published data directly comparing the two, but overall mortality in these conditions appears to be very similar. ^[3]

Rate Related

Rapid heart rates may produce significant symptoms in patients with pre-existing heart disease. Even in patients whose hearts are normal to start with, prolonged tachycardia tends to produce ventricular decompensation and heart failure.

Clot formation

Because there is little if any effective contraction of the atria there is stasis (pooling) of blood in the atria. In Anatomy, the atrium (plural atria) refers to a chamber or space Stasis of blood in susceptible individuals can lead to formation of thrombus (blood clots) within the heart. A thrombus, or blood clot, is the final product of the Blood coagulation step in Hemostasis. Thrombus is most likely to form in the atrial appendages. Clot in the left atrial appendage is particularly important since the left side of the heart supplies blood to the entire body. Thus, any thrombus material that dislodges from the this side of the heart can embolize to the brain, with the potentially devastating consequence of a stroke. In Medicine, an embolism occurs when an object (the embolus, plural emboli) migrates from one part of the Body (through circulation A stroke is the rapidly developing loss of brain functions due to a disturbance in the blood vessels supplying blood to the brain Thrombus material can of course embolize to any other portion of the body, though usually with a less severe outcome.

Sudden cardiac death

Sudden death is not directly associated with atrial flutter. However, in individuals with a pre-existing accessory conduction pathway, such as the bundle of Kent in Wolff-Parkinson-White syndrome, the accessory pathway may conduct activity from the atria to the ventricles at a rate that the AV node would usually block. The Bundle of Kent is an extra or accessory conduction pathway between the atria and ventricles in the heart Bypassing the AV node, the atrial rate of 300 beats/minute leads to a ventricular rate of 300 beats/minute (1:1 conduction). Even if the ventricles are able to sustain a cardiac output at such a high rates, 1:1 flutter with time may degenerate into ventricular fibrillation, causing hemodynamic collapse and death. Ventricular fibrillation ( V-fib or VF) is a condition in which there is uncoordinated contraction of the Cardiac muscle of the ventricles in the Death is the termination of the biological functions that define living Organisms It refers both to a specific

Treatment

In general, atrial flutter should be treated the same as atrial fibrillation. Atrial fibrillation ( AF or afib) is a Cardiac arrhythmia (abnormal heart rhythm that involves the two upper chambers ( atria) of the Heart Because both rhythms can lead to the formation of thrombus in the atria, individuals with atrial flutter usually require some form of anticoagulation or anti-platelet agent. A thrombus, or blood clot, is the final product of the Blood coagulation step in Hemostasis. Both rhythms can be associated with dangerously fast heart rate and thus require medication for rate and or rhythm control. Additionally, there are some specific considerations particular to treatment of atrial flutter.

Cardioversion

Atrial flutter is considerably more sensitive to electrical direct-current cardioversion than atrial fibrillation, and usually requires a lower energy shock. Conversely, it is relatively resistant to chemical cardioversion, and often deteriorates into atrial fibrillation prior to spontaneous return to sinus rhythm.

Ablation

Because of the reentrant nature of atrial flutter, it is often possible to ablate the circuit that causes atrial flutter. This is done in the electrophysiology lab by causing a ridge of scar tissue that crosses the path of the circuit that causes atrial flutter. Ablation of the isthmus, as discussed above, is a common treatment for typical atrial flutter.

See also

• Atrial fibrillation

References