II. Precautions

  1. Patients with Atrial Fibrillation are unreliable in judging Atrial Fibrillation duration (i.e. longer or shorter than 48 hours)
    1. Less than 70% of patients can actively predict when they are in paroxysmal Atrial Fibrillation
      1. Montenero (2004) J Interv Card Electrophysiol 10(3): 211-20
    2. Patients with Atrial Fibrillation are asymptomatic as often as 40-60% of the time
      1. Savelieva (2000) J Interv Card Electrophysiol 4(2):369-82
  2. Non-anticoagulated patients may form atrial thrombus at any time (even within 48 hours) and may not be detected by TEE
    1. Non-anticoagulated emergency department cardioversion-related Thromboembolism rate: <7% (mean 1.5%)
      1. Kinch (1995) Arch Intern Med 155(13): 1353-60
    2. Left atrial thrombus is present in 14% of non-anticoagulated patients with Atrial Fibrillation <48 hours (by TEE)
      1. Left atrial thrombus is present in 27% of non-anticoagulated patients with chronic Atrial Fibrillation
      2. Stoddard (1995) J Am Coll Cardiol 25(2): 452-9
    3. Thromboembolism occurs in 6% of cardioversion patients who had TEE prior to cardioversion without thrombus present
      1. May be secondary to acute clot formation from cardioversion-induced atrial stunning (may persist for days to weeks)
      2. Fatkin (1994) J Am Coll Cardiol 23(2): 307-16
  3. Cardioversion may not offer initial benefit for hemodynamically stable patients
    1. Spontaneous conversion to sinus rhythm occurs in 66% of patients within 24 hours and 80% within 48 hours
  4. Left Ventricular Dysfunction and valvular defect patients may have even less benefit (despite potentially increased atrial kick) and greater risk
    1. Atrial kick (10-15% of Cardiac Output) does not return for days to weeks after cardioversion (due to atrial stunning)
    2. Successful cardioversion rates are significantly worse in Left Ventricular Dysfunction
    3. Left Ventricular Dysfunction significantly increases the risk of Thromboembolism
  5. Caveat
    1. Emergent cardioversion is indicated in a hemodynamically unstable patient
    2. See Atrial Fibrillation Synchronized Cardioversion

III. Approach: Atrial Fibrillation Cardioversion if duration <48 hours (acute Atrial Fibrillation)

  1. See Atrial Fibrillation Cardioversion regarding precautions
  2. See precautions above (as Thromboembolism risk still exists despite short duration of Atrial Fibrillation)
  3. Consider Heparin while considering cardioversion
  4. Consider early Atrial Fibrillation Cardioversion
    1. Many patients prefer this when presenting with recurrence of Atrial Fibrillation to the Emergency Department
    2. Atrial Fibrillation is uncomfortable (Dyspnea, light headedness) and rate control medications have adverse effects
  5. Cardioversion options
    1. Atrial Fibrillation Synchronized Cardioversion (preferred)
      1. May be preceded by chemical cardioversion attempt (e.g. Ottawa protocol as below)
    2. Atrial Fibrillation Chemical Cardioversion
  6. Ottawa Aggressive Protocol
    1. First: Procainamide 1 g over 1 hour
    2. Next: Atrial Fibrillation Synchronized Cardioversion (if no effect with Procainamide)
    3. Efficacy
      1. Sinus rhythm conversion rate at time of ED discharge: 90%
      2. ED discharge rate: 97%
      3. Relapse rate: 9% at 7 days
    4. Safety
      1. No Thromboembolisms
    5. References
      1. Stiell (2007) Acad Emerg Med 14(5 Supplement 1): 59

IV. Approach: Atrial Fibrillation Protocol for cardioversion if duration more than 48 hours

  1. Warfarin (or other approved Anticoagulant) for 3 weeks before cardioversion
  2. Consider Atrial Fibrillation Cardioversion
  3. Continue Warfarin (or other approved Anticoagulant) for 4 weeks after cardioversion
    1. See Atrial Fibrillation Anticoagulation
  4. Early cardioversion ok if cleared with TEE first
    1. See Atrial Fibrillation Anticoagulation

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Ontology: Atrial Fibrillation (C0004238)

Definition (NCI) A supraventricular arrhythmia characterized by uncoordinated atrial myocardium activation due to multiple reentry circuits with consequent deterioration of atrial mechanical function. Instead of intermittently contracting, the atria quiver continuously in a chaotic pattern, causing a totally irregular, often tachycardia ventricular rate. On the ECG it is described by the replacement of consistent P waves by rapid oscillations or fibrillatory waves that vary in size, shape, and timing, associated with an irregular, frequently rapid ventricular response when atrioventricular conduction is intact. (NCI)
Definition (NCI) An arrhythmia in which minute areas of the atrial myocardium are in various uncoordinated stages of depolarization and repolarization; instead of intermittently contracting, the atria quiver continuously in a chaotic pattern, causing a totally irregular, often rapid ventricular rate.
Definition (NCI) A disorder characterized by a dysrhythmia without discernible P waves and an irregular ventricular response due to multiple reentry circuits. The rhythm disturbance originates above the ventricles.
Definition (CHV) rapid tremor and shake of upper chambers of the heart
Definition (CHV) rapid tremor and shake of upper chambers of the heart
Definition (CHV) rapid tremor and shake of upper chambers of the heart
Definition (CHV) rapid tremor and shake of upper chambers of the heart
Definition (CHV) rapid tremor and shake of upper chambers of the heart
Definition (CHV) rapid tremor and shake of upper chambers of the heart
Definition (MEDLINEPLUS)

An arrhythmia is a problem with the speed or rhythm of the heartbeat. Atrial fibrillation (AF) is the most common type of arrhythmia. The cause is a disorder in the heart’s electrical system.

Often, people who have AF may not even feel symptoms. But you may feel

  • palpitations -- an abnormal rapid heartbeat
  • shortness of breath
  • weakness or difficulty exercising
  • chest pain
  • dizziness or fainting
  • fatigue
  • confusion

AF can lead to an increased risk of stroke. In many patients, it can also cause chest pain, heart attack, or heart failure.

Doctors diagnose AF using family and medical history, a physical exam, and a test called an electrocardiogram (EKG), which looks at the electrical waves your heart makes. Treatments include medicines and procedures to restore normal rhythm.

NIH: National Heart, Lung, and Blood Institute

Definition (CSP) disorder of cardiac rhythm characterized by rapid, irregular atrial impulses and ineffective atrial contractions.
Definition (NCI) A supraventricular arrhythmia characterized by uncoordinated atrial myocardium activation due to multiple reentry circuits with consequent deterioration of atrial mechanical function. Instead of intermittently contracting, the atria quiver continuously in a chaotic pattern, causing a totally irregular, often tachycardia ventricular rate. On the ECG it is described by the replacement of consistent P waves by rapid oscillations or fibrillatory waves that vary in size, shape, and timing, associated with an irregular, frequently rapid ventricular response when atrioventricular conduction is intact.
Definition (MSH) Abnormal cardiac rhythm that is characterized by rapid, uncoordinated firing of electrical impulses in the upper chambers of the heart (HEART ATRIA). In such case, blood cannot be effectively pumped into the lower chambers of the heart (HEART VENTRICLES). It is caused by abnormal impulse generation.
Concepts Pathologic Function (T046)
MSH D001281
ICD9 427.31
ICD10 I48.0
SnomedCT 49436004, 155364009, 266306001
English Atrial Fibrillations, Auricular Fibrillation, Auricular Fibrillations, Fibrillations, Atrial, Fibrillations, Auricular, FIBRILLATION ATRIAL, ATRIAL FIBRILLATION, AURICULAR FIBRILLATION, Auricular fibrillation, Fibrillation, Atrial, Fibrillation, Auricular, AF, atrial fibrillation, atrial fibrillation (diagnosis), a fib, af, afib, Afib, AFib, Fibrillation atrial, Atrial Fibrillation [Disease/Finding], Fibrillation;atrial, atrial fibrillation (AF), auricular fibrillations, atrial fibrillations, Atrial fibrillation, AF - Atrial fibrillation, Atrial fibrillation (disorder), atrium; fibrillation, auricular; fibrillation, fibrillation; atrial or auricular, Fibrillation - atrial, Atrial Fibrillation, auricular fibrillation
French FIBRILLATION AURICULAIRE, FA, AFib, Fibrillation auriculaire, Fibrillation atriale
German VORHOFFLIMMERN, AF, Afib, Flimmern Vorhof, Herzohrflimmern, HERZVORHOFFLIMMERN, Vorhofflimmern, Aurikuläres Flimmern
Portuguese FIBRILACAO AURICULAR, FA, FIBRILHACAO AURICULAR, Fibrilhação auricular, Fibrilação Atrial, Fibrilação Auricular
Spanish FIBRILACION AURICULAR, FA, Fibrilación atrial, Atrial fibrillation, Fibrillation - atrial, AURICULAR, FIBRILACION, fibrilación auricular (trastorno), fibrilación auricular, Fibrilación auricular, Fibrilación Atrial, Fibrilación Auricular, Fibrilacion Atrial, Fibrilacion Auricular
Dutch AFib, AF, atriumfibrillatie, hartoorfibrilleren, atrium; fibrilleren, auriculair; fibrilleren, fibrilleren; atrium of auriculair, atriale fibrillatie, Atriumfibrillatie, Boezemfibrillatie, Fibrillatie, atrium-, Fibrillatie, boezem-, Fibrilleren, boezem-
Swedish Förmaksflimmer
Japanese シンボウサイドウ, 心房細動, 心房性細動
Finnish Eteisvärinä
Russian USHKA PREDSERDIIA FIBRILLIATSIIA, PREDSERDII FIBRILLIATSIIA, ПРЕДСЕРДИЙ ФИБРИЛЛЯЦИЯ, УШКА ПРЕДСЕРДИЯ ФИБРИЛЛЯЦИЯ
Czech Fibrilace ouška, Fibrilace síní, fibrilace síní, síňová fibrilace, FiS
Italian Fibrillazione auricolare, Fibrillazione atriale
Croatian ATRIJ, FIBRILACIJA
Polish Migotanie przedsionków
Hungarian AFib, Fibrillatio atrialis, Pitvarfibrillatio