Introduction
Background
Atrial flutter (AFL) is the second most common tachyarrhythmia, after atrial fibrillation. Much has been learned about the mechanism of atrial flutter in the past two decades and therefore how this arrhythmia is treated has changed. Radiofrequency catheter ablation is now the long-term treatment of choice in patients with symptomatic atrial flutter.
Atrial flutter has traditionally been characterized as a macro re-entrant arrhythmia with atrial rates between 240-400 beats per minute. The ECG usually demonstrates a regular rhythm, with P waves that can appear sawtoothed, also called flutter waves. Since the atrioventricular (AV) node cannot conduct at the same rate as the atrial activity, one commonly sees some form of conduction block, typically 2:1 or 4:1. This block may also be variable and cause atrial flutter to appear as an irregular rhythm.
Pathophysiology
Atrial flutter is caused by a reentrant circuit that is confined to the right atrium (RA). The impulses travel through the atrial septum, then across the right atrium, then inferiorly through the right atrium free wall, and then back across through an isthmus bounded by the coronary sinus os and the tricuspid valve annulus. This isthmus is also called the atrial flutter isthmus and is the target for radiofrequency catheter ablation of atrial flutter.
When the electric activity in this circuit moves in a counterclockwise direction, as described above, the atrial flutter is called typical atrial flutter. The ECG will demonstrate the classic negative sawtooth pattern in leads II, III, and aVF.
When the electric activity moves in a clockwise direction, the ECG will show positive flutter waves in leads II, III, and aVF, and may appear somewhat sinusoidal. This type of atrial flutter is called reverse typical atrial flutter.
Atrial flutter related to an incision made in the atria, as in congenital heart surgery, can also give rise to a re-entrant circuit. This causes incisional atrial re-entry.
Atrial flutter has been reported in rare cases to arise from the left atrium.
The above forms of atrial flutter are also called type I flutter. These are the most common forms.
Twelve-lead ECG of type I atrial flutter. Note negative sawtooth pattern of flutter waves in leads II, III, and aVF.
Type II atrial flutter, also known as atypical aflutter, is still poorly characterized, but may result from an intra-atrial re-entrant circuit operating at a faster rate.
Atrial flutter is associated in patients with heart failure, valvular disease, chronic obstructive pulmonary disease, hyperthyroidism, pericarditis, pulmonary embolism, and a history of open heart surgery.
Frequency
United States
Atrial flutter affects approximately 88 out of 100,000 new patients each year. In the United States, this represents approximately 200,000 patients presenting with atrial flutter annually.
Mortality/Morbidity
For the most part, morbidity and mortality are due to complications of rate (ie, syncope, congestive heart failure [CHF]). In patients who suffer from atrial flutter, the risk of embolic occurrences approaches that of atrial fibrillation.
Sex
Men are affected more often than women, with a 2:1 male-to-female ratio.
Age
The prevalence of atrial fibrillation increases with age and varies from 1 case out of 200 persons for people younger than 60 years, to almost 9 cases out of 100 persons for people older than 80 years.
- Aged 25-35 years: 2-3 cases per 1000 people
- Aged 55-64 years: 30-90 cases per 1000 people
- Aged 65-90 years: 50-90 cases per 1000 people
Clinical
History
Symptomatic atrial flutter is typically a manifestation of the rapid ventricular rate that decreases cardiac output.
- Palpitations
- Fatigue or poor exercise tolerance
- Mild dyspnea
- Presyncope
- Less common symptoms include angina, profound dyspnea, or syncope. Thromboembolic events are possible with this arrhythmia.
- Beware of the patient with a history of pre-excitation syndrome (Wolff-Parkinson-White), if they have a very short PR interval (<.115s) and no delta wave. Patients may experience 1:1 conduction of the flutter waves, and this can degenerate into ventricular fibrillation (VF).
Atrial flutter rhythm itself is unstable and usually reverts either to atrial fibrillation or sinus rhythm. It would be unusual for a patient to remain in stable chronic atrial flutter.
Physical
Pertinent physical findings are limited to cardiovascular system. If embolization has occurred from intermittent atrial flutter, findings are related to brain and/or peripheral vascular involvement.
- Tachycardia may or may not be present, depending on the degree of AV block associated with the atrial flutter activity.
- Cardiac rate, often approximately 150 beats per minute because of a 2:1 AV block (This is dependent on the atrial firing rate, which may be influenced by medications as well as intrinsic cardiac factors.)
- Regular or slightly irregular heartbeat, as the AV block may be variable
- Hypotension is possible, but normal blood pressure is observed more commonly.
- Peripheral embolization may occur
- Congestive heart failure (CHF) may be found, usually caused by left ventricle dysfunction.
Causes
- Patients at highest risk for atrial flutter include those with long-standing hypertension, valvular heart disease (rheumatic), left ventricular hypertrophy, coronary artery disease with or without depressed left ventricular function, pericarditis, pulmonary embolism, hyperthyroidism, and diabetes. Additionally, CHF for any reason is a noted contributor to this disorder.
- Additional causes include the following:
- Postoperative revascularization
- Digitalis toxicity
- Rare causes - Myotonic dystrophy in childhood1
More on Atrial Flutter |
 Overview: Atrial Flutter |
| Differential Diagnoses & Workup: Atrial Flutter |
| Treatment & Medication: Atrial Flutter |
| Follow-up: Atrial Flutter |
| Multimedia: Atrial Flutter |
| References |
| Further Reading |
| Next Page » |
References
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Sassone B, Leone O, Martinelli GN, Di Pasquale G. Acute myocardial infarction after radiofrequency catheter ablation of typical atrial flutter: histopathological findings and etiopathogenetic hypothesis. Ital Heart J. May 2004;5(5):403-7. [Medline].
Braunwald E. Heart disease: A Textbook of Cardiovascular Medicine. 5th ed. Philadelphia, Pa: WB Saunders Co; 1997:1997:641-656.
Galve E, Rius T, Ballester R, et al. Intravenous amiodarone in treatment of recent-onset atrial fibrillation: results of a randomized, controlled study. J Am Coll Cardiol. Apr 1996;27(5):1079-82. [Medline].
Goodacre S, Irons R. ABC of clinical electrocardiography: Atrial arrhythmias. BMJ. Mar 9 2002;324(7337):594-7. [Medline].
Gronefeld GC, Wegener F, Israel CW, Teupe C, Hohnloser SH. Thromboembolic risk of patients referred for radiofrequency catheter ablation of typical atrial flutter without prior appropriate anticoagulation therapy. Pacing Clin Electrophysiol. Jan 2003;26(1 Pt 2):323-7. [Medline].
Niebauer MJ, Chung MK. Management of atrial flutter. Cardiol Rev. Sep-Oct 2001;9(5):253-8. [Medline].
Perry JC, Fenrich AL, Hulse JE, Triedman JK, Friedman RA, Lamberti JJ. Pediatric use of intravenous amiodarone: efficacy and safety in critically ill patients from a multicenter protocol. J Am Coll Cardiol. Apr 1996;27(5):1246-50. [Medline].
Pritchett EL. Management of atrial fibrillation. N Engl J Med. May 7 1992;326(19):1264-71. [Medline].
Prystowsky EN, Benson DW Jr, Fuster V, et al. Management of patients with atrial fibrillation. A Statement for Healthcare Professionals. From the Subcommittee on Electrocardiography and Electrophysiology, American Heart Association. Circulation. Mar 15 1996;93(6):1262-77. [Medline].
Sawhney NS, Feld GK. Diagnosis and management of typical atrial flutter. Med Clin North Am. Jan 2008;92(1):65-85, x. [Medline].
Seidl K, Rameken M, Siemon G. Atrial flutter and thromboembolism risk. Cardiol Rev. 1999;16(12):25-28.
Vidaillet H, Granada JF, Chyou PH, et al. A population-based study of mortality among patients with atrial fibrillation or flutter. Am J Med. Oct 1 2002;113(5):365-70. [Medline].
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Further Reading
Clinical guidelines
ACC/AHA/ESC 2006 guidelines for the management of patients with atrial fibrillation. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation). European Heart Rhythm Association, Heart Rhythm Society, Zipes DP, Camm AJ, Borggrefe M, et al, American College of Cardiology, American Heart Association Task Force, European Society of Cardiology Committee for Practice Guidelines. ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association Task Force and the European Society [trunc]. J Am Coll Cardiol 2006 Sep5;48(5):e247-346. [1085 references] PubMed
Antithrombotic therapy in atrial fibrillation. American College of Chest Physicians evidence-based clinical practice guidelines (8th edition). Singer DE, Albers GW, Dalen JE, Fang MC, Go AS, Halperin JL, Lip GY, Manning WJ. Antithrombotic therapy in atrial fibrillation: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008 Jun;133(6 Suppl):546S-92S. [281 references] PubMed
Keywords
atrial flutter, heart flutter, auricular flutter, catheter ablation, atrial flutter treatment, atrial flutter causes, atrial flutter symptoms, atrial fibrillation, bradyarrhythmia, tachyarrhythmia, arrhythmia, heart disease, acute myocardial infarction, AMI, congestive heart disease, CHD, coronary artery disease, CAD, cardiovascular disease, heart attack, rhythm disturbance, palpitations, fatigue, poor exercise tolerance, dyspnea, angina, syncope, rhythm disturbance of the atria, congestive heart failure, CHF, peripheral embolization, left ventricle dysfunction, long-standing hypertension, valvular heart disease, rheumatic heart disease, left ventricular hypertrophy, diabetes, depressed left ventricular function, myotonic dystrophy, postoperative revascularization, digitalis toxicity, pulmonary embolism
