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| {{DiseaseDisorder infobox | | | __NOTOC__ |
| Name = Atrial flutter |
| | {| class="infobox" style="float:right;" |
| ICD10 = {{ICD10|I|48||i|30}} |
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| ICD9 = {{ICD9|427.32}} |
| | | [[File:Siren.gif|30px|link=Atrial flutter resident survival guide]]|| <br> || <br> |
| ICDO = |
| | | [[Atrial flutter resident survival guide|'''Resident'''<br>'''Survival'''<br>'''Guide''']] |
| Image = Common_Flutter.png |
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| Caption = Type I atrial flutter, counterclockwise rotation with 4:1 [[AV node|AV nodal]] block|
| | {{Atrial flutter}} |
| OMIM = |
| | {{Patient}} |
| OMIM_mult = |
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| MedlinePlus = 000184 |
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| eMedicineSubj = med |
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| eMedicineTopic = 185 |
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| DiseasesDB = 1072 |
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| }}
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| {{SI}} | |
| {{WikiDoc Cardiology Network Infobox}}
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| {{CMG}} | |
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| '''Associate Editor-In-Chief:''' {{CZ}}
| | {{CMG}}; {{AE}} {{CZ}} |
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| {{Editor Help}} | | {{SK}} A flutter; flutter |
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| ==Overview== | | ==[[Atrial flutter overview|Overview]]== |
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| '''Atrial flutter''' is an abnormal heart rhythm that occurs in the [[atrium (anatomy)|atria]] of the [[heart]]. When it first occurs, it is usually associated with a fast heart rate or [[tachycardia]], and falls into the category of [[supraventricular tachycardia|supra-ventricular tachycardias]]. 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. It is typically not a stable rhythm, and frequently degenerates into [[atrial fibrillation]]. However, it does rarely persist for months to years.
| | ==[[Atrial flutter historical perspective|Historical Perspective]]== |
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| ==Symptoms== | | ==[[Atrial flutter classification|Classification]]== |
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| While atrial flutter can sometimes go unnoticed, its onset is often marked by characteristic sensations of regular [[palpitation]]s. Such sensations usually last until the episode resolves, or until the heart rate is controlled.
| | ==[[Atrial flutter pathophysiology|Pathophysiology]]== |
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| Atrial flutter is usually well tolerated initially (fast heart beat 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. | | ==[[Atrial flutter causes|Causes]]== |
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| Prolonged fast flutter may lead to decompensation with loss of normal heart function ([[heart failure]]). This may manifest as effort intolerance (exertional breathlessness), nocturnal breathlessness, or swelling of the legs or abdomen.
| | ==[[Atrial flutter differential diagnosis|Differentiating Atrial flutter from other Diseases]]== |
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| ==Pathophysiology: mechanism of action== | | ==[[Atrial flutter risk factors|Risk Factors]]== |
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| Atrial flutter is caused by a [[Cardiac arrhythmia#Reentry|reentrant rhythm]] in either the right or left atrium. Typically initiated by a premature electrical impulse arising in the atria, atrial flutter is propogated due to differences in refractory periods of atrial tissue. This creates a self perpetuating loop of electrical activity moving around the atrium. | | ==[[Atrial flutter screening|Screening]]== |
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| 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 [[AV node|atrio-ventricular node]]. 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, ie. 2:1 block. The addition of rate-controlling drugs or conduction system disease can increase this block substantially (see image below).
| | ==[[Atrial flutter natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
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| [[Image:Line of Block.JPG|thumb|center|250px]] | | ==Diagnosis== |
| | | [[Atrial flutter history and symptoms|History and Symptoms]] | [[Atrial flutter physical examination|Physical Examination]] | [[Atrial flutter laboratory findings|Laboratory Findings]] | [[Atrial flutter electrocardiogram|Electrocardiogram]] | [[Atrial flutter EKG examples|EKG Examples]] | [[Atrial flutter chest x ray|Chest X Ray]] | [[Atrial flutter echocardiography|Echocardiography]] | [[Atrial flutter other imaging findings|Other Imaging Findings]] | [[Atrial flutter other diagnostic studies|Other Diagnostic Studies]] |
| There are two types of atrial flutter, the common '''type I''' and rarer '''type II'''.<sup>1</sup> 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.
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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 350 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 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.
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| 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.
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| Type II flutter follows a significantly different re-entry pathway to type I flutter, and is typically faster, usually 340–430 beats/minute.
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| ==Treatment== | | ==Treatment== |
| In general, atrial flutter should be [[Atrial fibrillation#Treatment|treated the same as atrial fibrillation]]. 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. 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.
| | [[Atrial flutter medical therapy|Medical Therapy]] | [[Atrial flutter surgery|Surgery]] | [[Atrial flutter primary prevention|Primary Prevention]] | [[Atrial flutter secondary prevention|Secondary Prevention]] | [[Atrial flutter cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Atrial flutter future or investigational therapies|Future or Investigational Therapies]] |
| | | ==Case Studies== |
| ===Cardioversion===
| | [[Atrial flutter case study one|Case #1]] |
| 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. | |
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| ===Ablation===
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| 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.
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| ==== Measurement of Successful Ablation ====
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| #Corridor of Widely split double potentials 90-110 ms
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| #Transisthmus Conduction Intervals
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| ##Counter Clockwise defined as interval between stimulus on lateral wall and proximal coronary sinus electrode.
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| ##Clockwise defined as interval between stimulus in proximal CS and electrodes lateral to line of block.
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| ##Interval measured at 500, 400, and 300 ms. If this value increased by 50% or more this was defined as successs or 150ms
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| #Pacing at multiple sites. AD>BD and DA>CA
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| #Bipolar electrograms lateral to line and pace from Proximal CS. Transition of polarity from positive to negative
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| #3 pacing site protocol: Pace at two sites lateral (L<sub>1</sub>R and L<sub>2</sub>R) to the line on block and on the septal site (S) of the line. Measure the conduction delay from the pacing site to the R wave on the QRS (L1 to R, L2 to R and S to R). If (L1R-L2R) > 0 and (L1R-SR) > 94 then there is a 100% sensitivity and 98% specificity.
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| ==Electrocardiographic Findings==
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| # There are rapid regular undulations (F waves) that cause a sawtooth appearance.
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| #* Best seen in 2,3,F and V1.
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| #* Usually inverted in the inferior leads.
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| #* No isoelectric baselines between the F waves.
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| # Atrial rate is 250 to 350 Beats Per Minute (BPM).
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| #* Can be faster in infants and children.
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| #* Massive dilation of the atria can lead to a rate < 200 BPM.
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| #* Quinidine can reduce the atrial rate.
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| # There is a variable ventricular rate depending on the AV conduction.
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| #* The Most common response is 2:1
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| #* 3:1 is uncommon
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| #* 4:1 suggests the existence of an AV conduction defect
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| #* May be associated with complete AV block in which case the RR intervals are regular and the F waves have no constant relationship to the QRS. The ventricular response is usually slow.
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| #* 1:1 conduction may be precipitated by excitement, exercise, induction of anesthesia or any increase in sympathetic tone. It may occur in WPW where the impulses are conducted antegrade through the bypass tract. All these are an emergency.
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| #* During treatment with quinidine the atrial rate may slow sufficiently to permit 1:1 conduction.
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| #* Vagal maneuvers increase the degree of AV block.
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| # QRS either normal or aberrant depending on preexisting IVCD or aberrant ventricular conduction.
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| ==Complications==
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| Although often regarded as a relatively benign 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<sup>3</sup>.
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| ===Rate Related===
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| 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.
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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 formation of [[thrombus]] (blood clots) within the heart. 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 [[embolism|embolize]] to the brain, 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 [[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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| ==Examples== | |
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| <gallery>
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| image:Aflutr_ecg.jpg|Atrial flutter
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| image:AFLUTTER.Variable.jpg|Atrial flutter with variable conduction
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| image:Aflutter1.1.jpg|A very rare condition 1:1 Atrial flutter
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| image:AFLUTTER2.1.jpg|2:1 Atrial flutter
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| image:AFLUTTER3.1.jpg|3:1 Atrial flutter
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| image:AFLUTTER4.1.jpg|4:1 Atrial flutter
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| image:AFLUTTER.RBBB.jpg|Atrial flutter with RBBB
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| Image:AFLtypical.jpg|Typical atrial flutter pattern
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| </gallery>
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| ==References==
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| #''Chou's Electrocardiography in Clinical Practice, Fifth Edition'', Surawicz & Knilans, ISBN 0-7216-8697-4
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| #''Electrophysiologic Testing'', Richard N. Fogoros, Blackwell Science, ISBN 0-632-04325-3
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| #Vidaillet, Granada, et.al. ''A Population-Based Study of Mortality among Patients with Atrial Fibrillation or Flutter'' '''The American Journal of Medicine''' 113:365-70
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| ==External Sources==
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| *[http://www.emedu.org/ecg_lib/index.htm A Great ECG Library]
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| *[http://en.ecgpedia.org/wiki/Main_Page A lot of Cases and ECG Examples]
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| ==External Links==
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| * [http://www.afadvisor.org/ Atrial Fibrillation Information - AF Advisor]
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| ==See also== | | ==Related Chapters== |
| * [[Atrial fibrillation]] | | * [[Atrial fibrillation]] |
| | * [[Multifocal atrial tachycardia]] |
| | * [[Supraventricular tachycardia]] |
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