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| {{distinguish|Atrial fibrillation}} | | {{Short description|A type of abnormal heart rhythm}} |
| | {{Use dmy dates|date=October 2023}} |
| {{Infobox medical condition (new) | | {{Infobox medical condition (new) |
| | name = Atrial flutter | | | name = Atrial flutter |
| | synonyms = | | | synonyms = AFL |
| | field = [[Cardiology]] | | | field = [[Cardiology]] |
| | image = Atrial_flutter34.svg | | | image = Atrial_flutter34.svg |
| | caption = Atrial flutter with varying A-V conduction (5:1 and 4:1) | | | caption = Atrial flutter with varying A-V conduction (5:1 and 4:1) |
| | pronounce = | | | pronounce = |
| | symptoms = | | | symptoms = [[Palpitations]], [[shortness of breath]], [[dizziness]], [[fatigue]], [[chest pain]] |
| | complications = | | | complications = [[Stroke]], [[heart failure]], [[cardiomyopathy]] |
| | onset = | | | onset = Sudden |
| | duration = | | | duration = May be intermittent or persistent |
| | types = | | | types = Typical (counterclockwise or clockwise), Atypical (non-cavotricuspid isthmus dependent) |
| | causes = | | | causes = [[Heart disease]], [[hypertension]], [[valvular heart disease]], [[pulmonary embolism]], [[hyperthyroidism]], post-cardiac surgery |
| | risks = | | | risks = [[Advancing age]], [[hypertension]], [[diabetes]], [[coronary artery disease]], [[heart failure]], previous [[atrial fibrillation]] |
| | diagnosis = | | | diagnosis = [[Electrocardiogram|ECG]], [[Holter monitor]], [[electrophysiology study]] |
| | differential = | | | differential = [[Atrial fibrillation]], [[supraventricular tachycardia]], [[sinus tachycardia]] |
| | prevention = | | | prevention = Control of underlying conditions, [[anticoagulation]] to reduce stroke risk |
| | treatment = | | | treatment = [[Electrical cardioversion]], [[catheter ablation]], [[rate control]] |
| | medication = | | | medication = [[Beta blockers]], [[calcium channel blockers]], [[amiodarone]], [[anticoagulants]] |
| | prognosis = | | | prognosis = Good with treatment; risk of recurrence without ablation |
| | frequency = | | | frequency = Common; more prevalent in older adults and individuals with heart disease |
| | deaths = | | | deaths = Rare with appropriate management; stroke can be fatal |
| }} | | }} |
| <!-- Definition and symptoms -->
| | [[File:Aflut.jpg|thumb|left|Atrial flutter with a two to one block. Note the P waves hiding in the T waves in leads V1 and V2]] |
| '''Atrial flutter''' ('''AFL''') is a common [[cardiac arrhythmia|abnormal heart rhythm]] that starts in the [[atrium (anatomy)|atrial chambers]] of the [[heart]].<ref name="Sawhney2009"/> When it first occurs, it is usually associated with a [[tachycardia|fast heart rate]] and is classified as a type of [[supraventricular tachycardia]].<ref name="Link2012">{{cite journal|last1=Link|first1=MS|title=Clinical practice. Evaluation and initial treatment of supraventricular tachycardia|journal=New England Journal of Medicine|date=October 2012|volume=367|issue=15|pages=1438–48|doi=10.1056/NEJMcp1111259|pmid=23050527}}</ref> 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 [[palpitation|a feeling of the heart beating too fast, too hard, or skipping beats]], chest discomfort, [[dyspnea|difficulty breathing]], a feeling as if one's stomach has dropped, a feeling of being light-headed, or [[Syncope (medicine)|loss of consciousness]]. | | [[Image:AtrialFlutter12.JPG|thumb|300px|right|Type I atrial flutter, counterclockwise rotation with 3:1 and 4:1 [[AV node|AV nodal]] block.]] |
| | '''Atrial flutter''' is a type of [[abnormal heart rhythm]] or [[arrhythmia]] that originates in the [[atria]] of the [[heart]]. It is characterized by a rapid, regular heartbeat and is often associated with [[atrial fibrillation]], another common type of arrhythmia. Atrial flutter can lead to significant symptoms and complications if not properly managed. |
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| <!-- Cause and Pathophysiology -->
| | ==Pathophysiology== |
| Although this abnormal heart rhythm typically occurs in individuals with cardiovascular disease (e.g. [[hypertension|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).<ref name="Bun2015"/> 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 [[thrombus|blood clots]] in the heart which pose a significant risk of breaking off and traveling through the bloodstream resulting in [[stroke]]s.
| | Atrial flutter occurs when there is a reentrant circuit within the right atrium. This circuit causes the atria to contract at a rapid rate, typically around 240 to 340 beats per minute. However, due to the refractory period of the [[atrioventricular node]], not all of these impulses are conducted to the [[ventricles]], resulting in a ventricular rate that is often slower, commonly around 150 beats per minute. |
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| <!-- Prevention and Treatment -->
| | The reentrant circuit in atrial flutter is usually a macro-reentrant circuit, which means it involves a large loop of electrical activity. This is in contrast to [[atrial fibrillation]], where the electrical activity is more chaotic and disorganized. |
| 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.<ref name="Link2012"/> Immediate treatment of atrial flutter centers on slowing the heart rate with medications such as [[beta blocker]]s (e.g., [[metoprolol]]) or [[calcium channel blocker]]s (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 [[hypotension|low blood pressure]] (unstable atrial flutter), then an urgent [[cardioversion|electrical shock to the heart]] to restore a normal heart rhythm is necessary. Long-term [[anticoagulation|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.<ref name="Bun2015"/><ref name="Vadmann2015">{{cite journal|last1=Vadmann|first1=H|last2=Nielsen|first2=PB|last3=Hjortshøj|first3=SP|last4=Riahi|first4=S|last5=Rasmussen|first5=LH|last6=Lip|first6=GY|last7=Larsen|first7=TB|title=Atrial flutter and thromboembolic risk: a systematic review|journal=Heart|date=September 2015|volume=101|issue=18|pages=1446–55|doi=10.1136/heartjnl-2015-307550|pmid=26149627}}</ref> [[Antiarrhythmic|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.<ref name="Sawhney2009">{{cite journal|last1=Sawhney|first1=NS|last2=Anousheh|first2=R|last3=Chen|first3=WC|last4=Feld|first4=GK|title=Diagnosis and management of typical atrial flutter|journal=Cardiology Clinics|date=February 2009|volume=27|issue=1|pages=55–67, viii|doi=10.1016/j.ccl.2008.09.010|pmid=19111764|type=Review}}</ref> 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).
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| <!-- Epidemiology -->
| | ==Symptoms== |
| Atrial flutter was first identified as an independent medical condition in 1920 by the British physician [[Thomas Lewis (cardiologist)|Sir Thomas Lewis]] (1881–1945) and colleagues.<ref>{{cite journal |vauthors=Lewis T, Feil HS, Stroud WD | title=Observations upon flutter, fibrillation, II: the nature of auricular flutter | journal=Heart | year=1920 | volume=7 | page=191}}</ref> 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).<ref name="Link2012"/><ref name="Bun2015">{{cite journal|last1=Bun|first1=SS|last2=Latcu|first2=DG|last3=Marchlinski|first3=F|last4=Saoudi|first4=N|title=Atrial flutter: more than just one of a kind|journal=European Heart Journal|date=September 2015|volume=36|issue=35|pages=2356–63|doi=10.1093/eurheartj/ehv118|pmid=25838435}}</ref> The overall incidence of AFL has been estimated at 88 cases per 100,000 [[person-year]]s. 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.<ref name="Bun2015"/>
| | Patients with atrial flutter may experience a variety of symptoms, including: |
| | * [[Palpitations]] |
| | * [[Shortness of breath]] |
| | * [[Fatigue]] |
| | * [[Dizziness]] or [[lightheadedness]] |
| | * [[Chest pain]] |
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| ==Signs and symptoms==
| | In some cases, atrial flutter may be asymptomatic and only discovered during a routine [[electrocardiogram]] (ECG). |
| While atrial flutter can sometimes go unnoticed, its onset is often marked by characteristic sensations of the heart feeling like it is [[palpitation|beating too fast or hard]]. Such sensations usually last until the episode resolves, or until the heart rate is controlled.
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| 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 [[dyspnea|shortness of breath]], chest pain, lightheadedness or dizziness, [[nausea]] and, in some patients, nervousness and feelings of impending doom.
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| 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.
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| ===Complications===
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| 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.<ref>{{cite journal |vauthors=Vidaillet H, Granada JF, Chyou PH, Maassen K, Ortiz M, Pulido JN | year = 2002 | title = A Population-Based Study of Mortality among Patients with Atrial Fibrillation or Flutter | url = | journal = The American Journal of Medicine | volume = 113 | issue = 5| pages = 365–70 | doi = 10.1016/S0002-9343(02)01253-6 | pmid = 12401530 |display-authors=etal}}</ref>
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| ====Rate related====
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| Rapid heart rates may produce significant symptoms in patients with pre-existing heart disease and can lead to [[ischemia|inadequate blood flow to the heart muscle]] and even [[myocardial infarction|a heart attack]].<ref name="Sawhney2009"/> 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]].<ref name="Sawhney2009"/> 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.
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| ====Clot formation====
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| Because there is little if any effective contraction of the [[atrium (anatomy)|atria]] there is stasis (pooling) of blood in the atria. Stasis of blood in susceptible individuals can lead to the formation of a [[thrombus]] (blood clot) within the heart. A thrombus is most likely to form in the [[Atrium (heart)|atrial appendages]]. A blood clot in the left atrial appendage is particularly important as the left side of the heart supplies blood to the entire body through the arteries. Thus, any thrombus material that dislodges from this side of the heart can [[embolism|embolize (break off and travel)]] to the brain's arteries, with the potentially devastating consequence of a [[stroke]]. Thrombus material can, of course, embolize to any other portion of the body, though usually with a less severe outcome.
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| ====Sudden cardiac death====
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| Sudden death is not directly associated with atrial flutter. However, in individuals with a pre-existing accessory conduction pathway, such as the [[Wolff-Parkinson-White syndrome#Bundle of Kent|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. 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]].
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| ==Pathophysiology==
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| Atrial flutter is caused by a [[Cardiac arrhythmia#Re-entry|re-entrant rhythm]]. This usually occurs along the cavo-tricuspid isthmus of the right atrium though atrial flutter can originate from the left atrium as well. Typically initiated by a [[Premature atrial contraction|premature electrical impulse arising in the atria]], atrial flutter is propagated due to differences in [[Refractory period (physiology)|refractory periods]] of atrial tissue. This creates electrical activity that moves in a localized self-perpetuating loop, which usually lasts about 200 milliseconds for the complete circuit. For each cycle around the loop, an electric impulse results and propagates through the atria.
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| The impact and symptoms of atrial flutter depend on the heart rate of the affected person. Heart rate is a measure of the ventricular rather than atrial activity. Impulses from the atria are conducted to the ventricles through the [[AV node|atrio-ventricular node (AV node)]]. In a person with atrial flutter, a 12-lead [[electrocardiogram|electrocardiogram (ECG)]] will demonstrate the atrial chambers of the heart contracting at a rate of 280–300 beats per minute whereas the ventricular chambers of the heart typically beat at a rate of 140–150 beats per minute.<ref name="Link2012"/> 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, for the example of a resting heart rate. (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]]. The addition of rate-controlling drugs or conduction system disease can increase this block substantially (see image below).
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| ==Diagnosis== | | ==Diagnosis== |
| Typical atrial flutter is recognized on an electrocardiogram by presence of characteristic "flutter waves" at a regular rate of 200 to 300 beats per minute. Flutter waves may not be evident on an ECG in atypical forms of atrial flutter. Individual flutter waves may be symmetrical, resembling p-waves, or may be asymmetrical with a "sawtooth" shape, rising gradually and falling abruptly or vice versa. If atrial flutter is suspected clinically but is not clearly evident on ECG, acquiring a [[Lewis lead]] ECG may be helpful in revealing flutter waves.
| | The diagnosis of atrial flutter is typically made using an [[electrocardiogram]] (ECG). The ECG will show a characteristic "sawtooth" pattern of atrial activity, known as "F-waves," particularly in the inferior leads (II, III, and aVF). The ventricular rate is often regular and can be a multiple of the atrial rate, commonly 2:1 conduction. |
| ===Classification===
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| There are two types of atrial flutter, the common ''type I'' and rarer ''type II''.<ref>{{Cite book |author1=Surawicz, Borys |author2=Knilans, Timothy K. |author3=Chou, Te-Chuan |title=Chou's electrocardiography in clinical practice: adult and pediatric | year=2001 | publisher=Saunders | location=Philadelphia | isbn=978-0-7216-8697-4 | pages=}}{{page?|date=May 2018}}</ref> Most individuals with atrial flutter will manifest only one of these. Rarely someone may manifest both types; however, they can manifest only one type at a time.
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| ====Type I====
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| [[Image:AtrialFlutter12.JPG|thumb|300px|right|Type I atrial flutter, counterclockwise rotation with 3:1 and 4:1 [[AV node|AV nodal]] block.]]
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| [[File:Aflut.jpg|thumb|300px|Atrial flutter with a two to one block. Note the P waves hiding in the T waves in leads V1 and V2]]
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| Type I atrial flutter, also known as common atrial flutter or typical atrial flutter, has an atrial rate of 240 to 340 beats/minute. However, this rate may be slowed by [[antiarrhythmic agents]].
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| The reentrant loop circles the right atrium, passing through the [[cavo-tricuspid isthmus]] – a body of fibrous tissue in the lower atrium between the [[inferior vena cava]], and the [[tricuspid valve]].<ref name="Sawhney2009"/> 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.<ref name="Sawhney2009"/>
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| * 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.<ref name="Sawhney2009"/>
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| * The re-entry loop cycles in the opposite direction in clockwise atrial flutter, thus the flutter waves are upright in II, III, and aVF.<ref name="Sawhney2009"/>
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| ====Type II====
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| Type II (atypical) atrial flutter follows a significantly different re-entry pathway to type I flutter, and is typically faster, usually 340–350 beats/minute.<ref name="urlAtrial Flutter: Overview - eMedicine Cardiology">{{cite web |url=http://emedicine.medscape.com/article/151210-overview |title=Atrial Flutter: Overview|work= eMedicine Cardiology |accessdate=2009-03-06| archiveurl= https://web.archive.org/web/20090226110544/http://emedicine.medscape.com/article/151210-overview| archivedate= 26 February 2009 | url-status= live}}</ref> Atypical atrial flutter rarely occurs in people who have not undergone previous heart surgery or previous catheter ablation procedures. Left atrial flutter is considered atypical and is common after incomplete left atrial ablation procedures.<ref name="Garan2008">{{cite journal|last1=Garan|first1=H|title=Atypical atrial flutter|journal=Heart Rhythm|date=April 2008|volume=5|issue=4|pages=618–21|doi=10.1016/j.hrthm.2007.10.031|pmid=18325846}}</ref> Atypical atrial flutter originating from the right atrium and heart's septum have also been described.
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| ==Management== | | ==Treatment== |
| In general, atrial flutter should be [[Management of atrial fibrillation|managed the same as atrial fibrillation]]. Because both rhythms can lead to the formation of a [[thrombus|blood clot]] in the atrium, individuals with atrial flutter usually require some form of [[anticoagulant|anticoagulation]] or [[antiplatelet]] agent. Both rhythms can be associated with dangerously fast heart rates and thus require medication to control the heart rate (such as [[beta blocker]]s or [[calcium channel blocker]]s) and/or rhythm control with [[class III antiarrhythmic]]s (such as [[ibutilide]] or [[dofetilide]]). However, atrial flutter is more resistant to correction with such medications than atrial fibrillation.<ref name="Sawhney2009"/> For example, although the class III antiarrhythmic agent ibutilide is an effective treatment for atrial flutter, rates of recurrence after treatment are quite high (70–90%).<ref name="Sawhney2009"/> Additionally, there are some specific considerations particular to treatment of atrial flutter.
| | The treatment of atrial flutter aims to control the heart rate, restore normal rhythm, and prevent complications such as [[stroke]]. Treatment options include: |
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| ===Cardioversion===
| | * '''Rate control:''' Medications such as [[beta-blockers]] or [[calcium channel blockers]] can be used to slow the ventricular rate. |
| | * '''Rhythm control:''' [[Cardioversion]] can be performed to restore normal sinus rhythm. This can be done electrically or with medications such as [[ibutilide]]. |
| | * '''Catheter ablation:''' This procedure involves destroying the reentrant circuit in the right atrium using radiofrequency energy, which can provide a long-term solution to atrial flutter. |
| | * '''Anticoagulation:''' Patients with atrial flutter are at increased risk of [[thromboembolism]], and anticoagulation therapy may be necessary to reduce the risk of [[stroke]]. |
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| Atrial flutter is considerably more sensitive to electrical [[direct current cardioversion]] than atrial fibrillation, with a shock of only 20 to 50 Joules commonly being enough to cause a return to a normal heart rhythm (sinus rhythm). Exact placement of the pads does not appear important.<ref>{{cite journal|last1=Kirkland|first1=S|last2=Stiell|first2=I|last3=AlShawabkeh|first3=T|last4=Campbell|first4=S|last5=Dickinson|first5=G|last6=Rowe|first6=BH|title=The efficacy of pad placement for electrical cardioversion of atrial fibrillation/flutter: a systematic review.|journal=Academic Emergency Medicine|date=July 2014|volume=21|issue=7|pages=717–26|pmid=25117151|doi=10.1111/acem.12407}}</ref>
| | ==Prognosis== |
| | The prognosis for patients with atrial flutter varies depending on the underlying cause and the presence of other medical conditions. With appropriate treatment, many patients can achieve good control of their symptoms and reduce the risk of complications. |
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| ===Ablation=== | | ==Related pages== |
| Due to the reentrant nature of atrial flutter, it is often possible to ablate the circuit that causes atrial flutter with [[radiofrequency catheter ablation]]. Catheter ablation is considered to be a first-line treatment method for many people with typical atrial flutter due to its high rate of success (>90%) and low incidence of complications.<ref name="Sawhney2009"/> This is done in the cardiac electrophysiology lab by causing a ridge of scar tissue in the cavotricuspid isthmus that crosses the path of the circuit that causes atrial flutter. Eliminating conduction through the isthmus prevents reentry, and if successful, prevents the recurrence of the atrial flutter. Atrial fibrillation often occurs (30% within 5 years) after catheter ablation for atrial flutter.<ref name="Sawhney2009"/>
| | * [[Atrial fibrillation]] |
| | * [[Arrhythmia]] |
| | * [[Electrocardiogram]] |
| | * [[Cardioversion]] |
| | * [[Catheter ablation]] |
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| ==References==
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| {{reflist}}
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| == External links == | | == External links == |
| {{Medical resources | | {{Medical resources |
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| }} | | }} |
| {{Circulatory system pathology}} | | {{Circulatory system pathology}} |
| | | {{stub}} |
| {{DEFAULTSORT:Atrial Flutter}} | | {{DEFAULTSORT:Atrial Flutter}} |
| [[Category:Cardiology]] | | [[Category:Cardiology]] |
| [[Category:Cardiac arrhythmia]] | | [[Category:Cardiac arrhythmia]] |
| [[Category:Heart diseases]] | | [[Category:Heart diseases]] |
| | [[Category:Cardiac arrhythmia]] |
