Atrial fibrillation

Revision as of 15:25, 15 June 2009 by Swilliams (talk | contribs)
Jump to navigation Jump to search
Conduction
Sinus rhythm
Atrial fibrillation
Atrial fibrillation
The P waves, which represent depolarization of the atria, are irregular or absent during atrial fibrillation.
ICD-10 I48
ICD-9 427.31
DiseasesDB 1065
MedlinePlus 000184
eMedicine med/184  emerg/46

WikiDoc Resources for Atrial fibrillation

Articles

Most recent articles on Atrial fibrillation

Most cited articles on Atrial fibrillation

Review articles on Atrial fibrillation

Articles on Atrial fibrillation in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Atrial fibrillation

Images of Atrial fibrillation

Photos of Atrial fibrillation

Podcasts & MP3s on Atrial fibrillation

Videos on Atrial fibrillation

Evidence Based Medicine

Cochrane Collaboration on Atrial fibrillation

Bandolier on Atrial fibrillation

TRIP on Atrial fibrillation

Clinical Trials

Ongoing Trials on Atrial fibrillation at Clinical Trials.gov

Trial results on Atrial fibrillation

Clinical Trials on Atrial fibrillation at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Atrial fibrillation

NICE Guidance on Atrial fibrillation

NHS PRODIGY Guidance

FDA on Atrial fibrillation

CDC on Atrial fibrillation

Books

Books on Atrial fibrillation

News

Atrial fibrillation in the news

Be alerted to news on Atrial fibrillation

News trends on Atrial fibrillation

Commentary

Blogs on Atrial fibrillation

Definitions

Definitions of Atrial fibrillation

Patient Resources / Community

Patient resources on Atrial fibrillation

Discussion groups on Atrial fibrillation

Patient Handouts on Atrial fibrillation

Directions to Hospitals Treating Atrial fibrillation

Risk calculators and risk factors for Atrial fibrillation

Healthcare Provider Resources

Symptoms of Atrial fibrillation

Causes & Risk Factors for Atrial fibrillation

Diagnostic studies for Atrial fibrillation

Treatment of Atrial fibrillation

Continuing Medical Education (CME)

CME Programs on Atrial fibrillation

International

Atrial fibrillation en Espanol

Atrial fibrillation en Francais

Business

Atrial fibrillation in the Marketplace

Patents on Atrial fibrillation

Experimental / Informatics

List of terms related to Atrial fibrillation

Cardiology Network

Discuss Atrial fibrillation further in the WikiDoc Cardiology Network
Adult Congenital
Biomarkers
Cardiac Rehabilitation
Congestive Heart Failure
CT Angiography
Echocardiography
Electrophysiology
Cardiology General
Genetics
Health Economics
Hypertension
Interventional Cardiology
MRI
Nuclear Cardiology
Peripheral Arterial Disease
Prevention
Public Policy
Pulmonary Embolism
Stable Angina
Valvular Heart Disease
Vascular Medicine

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]

Please Join in Editing This Page and Apply to be an Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [3] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.

Synonyms and related keywords: AF, Afib, fib

Overview

Overview

Epidemiology

Diagnosis

Overview

Classification

Etiology and Differential Diagnosis

Treatment

Pharmacological Treatment

Invasive Treatment

Surgical Treatment

Invasive treatment of atrial fibrillation

Radiofrequency ablation

In patients with AF where rate control drugs are ineffective and it is not possible to restore sinus rhythm using cardioversion, non-pharmacological alternatives are available. For example, to control rate it is possible to destroy the bundle of cells connecting the upper and lower chambers of the heart - the atrioventricular node - which regulates heart rate, and to implant a pacemaker instead. A more complex technique, which avoids the need for a pacemaker, involves ablating groups of cells near the pulmonary veins where atrial fibrillation is thought to originate, or creating more extensive lesions in an attempt to prevent atrial fibrillation from establishing itself.[1]

Ablation is a newer technique and has shown some promise for cases of recurrent AF that are unresponsive to conventional treatments. Radiofrequency ablation (RFA) uses radiofrequency energy to destroy abnormal electrical pathways in heart tissue. The energy emitting probe (electrode) is placed into the heart through a catheter inserted into veins in the groin or neck. Electrodes that can detect electrical activity from inside the heart are also inserted, and the electrophysiologist uses these to "map" an area of the heart in order to locate the abnormal electrical activity before eliminating the responsible tissue.

Most AF ablations consist of isolating the electrical pathways from the pulmonary veins (PV)[2], which are located on the posterior wall of the left atrium. All other veins from the body (including neck and groin) lead to the right atrium, so in order to get to the left atrium the catheters must get across the atrial septum. This is done by piercing a small hole in the septal wall. This is called a transseptal approach. Once in the left atrium, the physician may perform Wide Area Circumferential Ablation (WACA) to electrically isolate the PVs from the left atrium.[3]

Some more recent approaches to ablating AF is to target sites that are particularly disorganized in both atria as well as in the coronary sinus (CS). These sites are termed complex fractionated atrial electrogram (CFAE) sites.[4]. It is believed by some that the CFAE sites are the cause of AF, or a combination of the PVs and CFAE sites are to blame. New techniques include the use of cryoablation (tissue freezing using a coolant which flows through the catheter), microwave ablation, where tissue is ablated by the microwave energy "cooking" the adjacent tissue, and high intensity focused ultrasound (HIFU), which destroys tissue by heating. This is an area of active research, especially with respect to the RF ablation technique and emphasis on isolating the pulmonary veins that enter into the left atrium.

Efficacy and risks of catheter ablation of atrial fibrillation are areas of active debate. A worldwide survey of the outcomes of 8745 ablation procedures[5] demonstrated a 52% success rate (ranging from 14.5% to 76.5% among centers), with an additional 23.9% of patients becoming asymptomatic with addition of an antiarrhythmic medication. In 27.3% of patients, more than one procedure was required to attain these results. There was at least one major complication in 6% of patients. A thorough discussion of results of catheter ablation was published in 2007[6]; it notes that results are widely variable, due in part to differences in technique, follow-up, definitions of success, use of antiarrhythmic therapy, and in experience and technical proficiency.

Surgical treatment of atrial fibrillation

Maze procedure

James Cox, MD, and associates developed the Cox maze procedure, an open-heart surgical procedure intended to eliminate atrial fibrillation, and performed the first one in 1987. "Maze" refers to the series of incisions made in the atria, which are arranged in a maze-like pattern. The intention was to eliminate AF by using incisional scars to block abnormal electrical circuits (atrial macro reentry) that AF requires. This procedure required an extensive series of endocardial (from the inside of the heart) incisions through both atria, a median sternotomy (vertical incision through the breastbone) and cardiopulmonary bypass (heart-lung machine). A series of improvements were made, culminating in 1992 in the Cox maze III procedure, which is now considered to be the "gold standard" for effective surgical cure of AF. The Cox maze III is sometimes referred to as the "traditional maze", the "cut and sew maze", or simply the "maze".[7]

Minimaze surgery is minimally invasive cardiac surgery similarly intended to cure atrial fibrillation. The "Minimaze" procedure refers to "mini" versions of the original maze procedure. These procedures are less invasive than the Cox maze procedure and do not require a median sternotomy (vertical incision in the breastbone) or cardiopulmonary bypass (heart-lung machine). These procedures use microwave, radiofrequency, or acoustic energy to ablate atrial tissue near the pulmonary veins.

Prognosis

Follow up & Secondary prevention

Risk factors for ischemic stroke or systemic embolization in patient with non valvular atrial fibrillation

Numbers represents relative risks[8]

  1. Advanced age (continuous, per decade) 1.4
  2. History of hypertension 1.6
  3. Heart failure or impaired left ventricular systolic function 1.4
  4. Coronary artery disease (CAD) 1.5
  5. Diabetes mellitus (DM) 1.7
  6. Previous stroke or Transient Ischemic Attack (TIA) 2.5

Clinical Trial Data

Results from the Pulmonary Vein Antrum Isolation versus AV Node Ablation with Bi-Ventricular Pacing for Treatment of Atrial Fibrillation in Patients with Congestive Heart Failure (PABA-CHF) study suggest that pulmonary-vein (PV) isolation leads to better morphologic and functional results than atrioventricular (AV) node ablation with biventricular pacing for congestive heart failure (CHF) in patients with atrial fibrillation.

In this prospective, multicenter study, 41 patients were randomized to PV isolation and 40 to AV node ablation with biventricular pacing. At 6 months, patients in the PV isolation group had higher mean ejection fractions (35% vs 29%, p<0.001), greater 6 minute distances walked (340 vs 297 meters, p <0.001), and better quality of life scores as determined by the Minnesota Living with Heart Failure questionnaire (60 vs 82, p<0.001, where lower scores indicate better quality of life) than those in the AV node ablation arm.

These PABA-CHF study findings thus suggest the potential advantages of performing PV isolation over AV node ablation with biventricular pacing for this patient population.

Noted limitations of the study include using sites with extensive experience in performing ablations, an unblinded study design, and a relatively short follow-up time. (NEJM by Mohammed N. Khan, et al.)

Guidelines: Diagnosis and Management of Atrial Fibrillation

External links

See also

EKG Examples of atrial fibrillation

External EKG Sources

References

  1. The Cleveland Clinic
  2. Medscape
  3. Nademanee K, McKenzie J, Kosar E, Schwab M, Sunsaneewitayakul B, Vasavakul T, Khunnawat C, Ngarmukos T. (2004). "A new approach for catheter ablation of atrial fibrillation: mapping of the electrophysiologic substrate". J Am Coll Cardiol. 43 (11): 2044–53. doi:10.1016/j.jacc.2003.12.054. PMID 15172410.
  4. Cappato R, Calkins H, Chen SA, Davies W, Iesaka Y, Kalman J, Kim YH, Klein G, Packer D, Skanes A. (2005). "Worldwide survey on the methods, efficacy, and safety of catheter ablation for human atrial fibrillation". Circulation. 111: 1100–1105. doi:10.1161/01.CIR.0000157153.30978.67. PMID 15723973.
  5. Calkins H, Brugada J, Packer DL, Cappato R, Chen SA, Crijns HJ, Damiano RJ Jr, Davies DW, Haines DE, Haissaguerre M, Iesaka Y, Jackman W, Jais P, Kottkamp H, Kuck KH, Lindsay BD, Marchlinski FE, McCarthy PM, Mont JL, Morady F, Nademanee K, Natale A, Pappone C, Prystowsky E, Raviele A, Ruskin JN, Shemin RJ. (2007). "HRS/EHRA/ECAS expert Consensus Statement on catheter and surgical ablation of atrial fibrillation: recommendations for personnel, policy, procedures and follow-up. A report of the Heart Rhythm Society (HRS) Task Force on catheter and surgical ablation of atrial fibrillation". Heart Rhythm. 4 (6): 816–61. PMID 17556213.
  6. Cox JL, Schuessler RB, Lappas DG, Boineau JP (1996). "An 8 1/2-year clinical experience with surgery for atrial fibrillation". Ann. Surg. 224 (3): 267–73, discussion 273-5. PMID 8813255.
  7. Estes NAM 3rd, Halperin JL, Calkins H, Ezekowitz MD, Gitman P, Go AS, McNamara RL, Messer JV, Ritchie JL, Romeo SJW, Waldo AL, Wyse DG. ACC/AHA/Physician Consortium 2008 clinical performance measures for adults with non valvular atrial fibrillation or atrial flutter: a report of the American College of Cardiology/American Heart Association Task Force on Performance Measures and the Physician Consortium for Performance Improvement (Writing Committee to Develop Performance Measures for Atrial Fibrillation). Circulation 2008; 117:1101–1120

Further Readings

  • Fuster V, Rydén LE, Cannom DS, et al (2006). "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): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society". Circulation 114 (7): e257-354. doi:10.1161/CIRCULATIONAHA.106.177292. PMID 16908781.
  • Estes NAM 3rd, Halperin JL, Calkins H, Ezekowitz MD, Gitman P, Go AS, McNamara RL, Messer JV, Ritchie JL, Romeo SJW, Waldo AL, Wyse DG. ACC/AHA/Physician Consortium 2008 clinical performance measures for adults with non valvular atrial fibrillation or atrial flutter: a report of the American College of Cardiology/American Heart Association Task Force on Performance Measures and the Physician Consortium for Performance Improvement (Writing Committee to Develop Performance Measures for Atrial Fibrillation). Circulation 2008; 117:1101–1120
  • Braunwald's Heart Disease, Libby P, 8th ed., 2007, ISBN 978-1-41-604105-4
  • Hurst's the Heart, Fuster V, 12th ed. 2008, ISBN 978-0-07-149928-6
  • Willerson JT, Cardiovascular Medicine, 3rd ed., 2007, ISBN 978-1-84628-188-4

Template:SIB

de:Vorhofflimmern it:Fibrillazione atriale nl:Boezemfibrilleren no:Atrieflimmer fi:Eteisvärinä


Template:WikiDoc Sources