Signs and symptoms:
- None
- Palpitations
- Dyspnea
- Fatigue
- CHF
- Angina
- Syncope
- Stroke
DIAGNOSTIC TESTS & INTERPRETATION 
- EKG
- Ambulatory monitor or event monitor (especially useful if AF paroxysmal)
- Echo to evaluate structural heart disease (myocardial and valvular)
- Rule out hyperthyroidism
Imaging
Cardiac catheterization and angiography if ischemia and/or coronary artery disease are suspected
DIFFERENTIAL DIAGNOSIS
- Atrial flutter (regular and irregular)
- Multifocal atrial tachycardia (irregular)
- Atrial tachycardia (regular)
- Atrioventricular (AV) reentrant and AV nodal reentrant tachycardias (regular)
- Junctional tachycardia (regular)
Outline
ADDITIONAL TREATMENT
General Measures
- The relative risk of stroke is reduced by 60–80% with anticoagulation therapy with warfarin.
- The CHADS score allows stroke risk stratification in nonvalvular atrial fibrillation. In patients with atrial fibrillation and mitral valve disease or hypertrophic cardiomyopathy, chronic anticoagulation is almost always indicated
- A CHADS score
2 generally warrants therapy with Coumadin, a score of 0 allows therapy with aspirin, a score of 1 therapy with aspirin or Coumadin is appropriate. - Symptoms and quality of life can be improved either by controlling the ventricular response or by restoring sinus rhythm.
- The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Trial showed no difference in survival in 4,000 patients (mean age 69 yr) with AF randomized to either heart rate control or rhythm control.
- The decision to convert to sinus rhythm depends on an assessment of the likelihood of maintaining sinus rhythm (here duration of AF, left atrial size, and LV function are important factors) and of relative risks and benefits of the procedure:
- Benefits of restoring sinus rhythm include the possibilities of fewer symptoms related to AF and in low-risk patients stopping anticoagulation.
- Risks relate to potential for proarrhythmia from antiarrhythmic drugs, bradycardia, and an increased chance for adverse drug reactions.
- Rate-control strategy may be less costly.
- Patients left in AF with a controlled ventricular response may have more symptoms, and may need continued anticoagulation based on their CHADS score.
- Rate control can be accomplished by either drug therapy or AV node ablation with pacemaker implantation.
- Conversion to sinus rhythm can be accomplished by drug therapy or by synchronized electrical cardioversion.
- Cardioversion should be immediate when there is hemodynamic instability, ongoing angina, or CHF.
- Rapid conduction of AF over an accessory pathway in the Wolff-Parkinson-White syndrome is also an indication for emergent cardioversion.
- Patients with less severe signs or symptoms can be cardioverted electively.
- In the absence of an urgent indication, patients who are not therapeutically anticoagulated (INR >2; at least for 3 wk) when the duration of AF is unknown or >48 hr should not be cardioverted.
- Patients with an ECG showing left atrial thrombus or a predictor of stroke (such as mitral stenosis or echo smoke) should be therapeutically anticoagulated for at least 3 wk.
- Patients with frequent recurrences of AF despite multiple prior antiarrhythmic drug trials would not be anticipated to maintain sinus rhythm and therefore should not be converted.
- AF with a slow ventricular response may also have sick sinus syndrome or drug-induced sinus node suppression. They may have significant sinus bradycardia after cardioversion of atrial fibrillation. For these patients, AV nodal blocking drugs should be held 12–24 hr before cardioversion and/or rate support should be available at the time cardioversion; for example, with a temporary or permanent transvenous pacemaker.
- For patients refractory to medical therapy a surgical options to maintain sinus rhythm include the MAZE procedure, while designed as stand-alone therapy, it is now mostly performed in conjunction with other cardiac surgery.
- For patients refractory to medical therapy, the catheter-based left atrial ablation/pulmonary vein ablation shows great promise. Current data suggest 70–80% success in patients with paroxysmal AF, 50–60% success in patients with permanent AF. These are complex procedures, the risk of complications is <2–3% but includes death, stroke, pulmonary vein stenosis, cardiac tamponade, damage to extracardiac structures such as the phrenic nerve, esophagus (fistula, almost always lethal), bronchus/lung tissue, vagal nerve.
- Atrial defibrillators are rarely if ever used anymore.
- Usually no restrictions on activity, and dietary recommendations are made as appropriate for underlying disease or syndrome such as diabetes, coronary artery disease, heart failure, and HTN.
SURGERY
- Surgical MAZE procedure, as discussed above
- Catheter-based AV node ablation (or modification) and implantation of pacemaker (dual-chamber if AF paroxysmal), especially in patients with fast, difficult to control ventricular rates
- Specialized atrial pacing techniques (dual-site and dual-chamber atrial-based pacing), especially in patients with a pacing indications (overall benefit appears small)
- Atrial implantable defibrillator, no longer in clinical use
- Possible cure with a surgical MAZE procedure, as discussed above, newer techniques deliver ablation lesions epicardially, using various energy forms (cryo-lesions, US lesions, radiofrequency energy), surgical approach: Open heart or minimal invasive (mostly performed as adjunct to other heart surgery)
- Transvenous catheter-based left atrial ablation; highly skilled EP labs have reported very encouraging results, particularly in patients with paroxysmal AF, see discussion above.
IN-PATIENT CONSIDERATIONS
Admission Criteria
- Patients can often be treated for AF on a completely outpatient basis.
- Criteria for admission include complications of AF such as:
- Uncontrolled ventricular response
- Heart failure or angina as a consequence of AF
- Initiation of antiarrhythmic drug therapy (especially in patients with structural heart disease at increased risk for proarrhythmia)
- Controversy exists as to who needs to be admitted for antiarrhythmic drug initiation, with considerations being:
- Age (and hence drug metabolism)
- Underlying heart disease with proarrhythmia potential
Outline
FOLLOW-UP RECOMMENDATIONS
Patient Monitoring
- Anticoagulation followed with INR that should be 2–3 for optimal protection against embolization and minimization of risk for bleeding; start warfarin carefully, close follow up of INR initially (ie, weekly)
- Risk of thromboembolism increases with INR <2.0, risk of CNS bleed increases with INR >4.0
- Follow EKG and response to antiarrhythmic drugs, especially QT interval, heart rate (HR), and PR interval. Watch for ventricular proarrhythmia related to antiarrhythmic drug therapy.
- Assess ventricular rate control if in permanent/persistent AF with Holter or ambulatory monitoring. Criteria used in the AFFIRM trial were: Rest HR <80 bpm, HR with hall walk <110 bpm)
PATIENT EDUCATION
- Importance of anticoagulation and control of INR to prevent stroke
- Be vigilant for bleeding as consequence of anticoagulation, and proarrhythmia from antiarrhythmic drugs.
PROGNOSIS
- Depends on age and population in question
- Young people with "lone" AF (no predisposing cause, <65 yr of age) have normal prognosis even without anticoagulation.
- Elderly patients with risk factor for stroke have risk ratio of >12 for stroke and death.
- AF can best be prevented by treating and preventing reversible risk factors [ie, HTN, CHF (CHF)].
Outline
CODES
ICD9
427.31 Atrial fibrillation
SNOMED
-blocker (