Atrial Fibrillation: Overview and Management

1. Atrial Fibrillation Overview and Management

2. What is it? • Most commonly seen narrow complex arrythmia. • Most common irregularly irregular rhythm • Affects more than 10% of age >80. • Men > Women • Multiple impulses from different areas move toward the AV node. • Produce an irregular ventricular response • Rate depends on # of impulses conducted.

3. Why is it important? • Can cause significant symptoms usually secondary to RVR • Range from severe (pulm edema, palpitations, angina, syncope) to none at all • Prolonged tachycardia may lead to cardiomyopathy • May lead to clot formation and eventually a embolic stroke. • Irregular contractions lead to stasis

4. Classification • Paroxysmal – end <7 days • Persistent – last > 7 days • May terminate on its own or by cardioversion • Permanent - > 1 year and cardioversion has not been attempted or failed • Lone AF – any of the above without structural heart disease • Only applies to AF unrelated to a reversible cause

5. Causes/Associations • Cardiac Surgery • Pericarditis • MI • Hyperthyroidism • PE • Pulmonary disease • Stress, Fever, Excessive EtOH intake, Dehydr. • Treat associated cause and the abnormal rhythm

6. Diagnosis • History and PE – onset, pattern, frequency, symptoms, precipitating factors, other diseases • Symptoms related to severity of underlying heart disease • EKG – no p waves, irregularly irregular rhythm, tachycardia

7. What do we do about it?Four Issues • Rhythm control • Rate control • Choosing between the two • Prevention of emboli ۞ Choice depends on the type, patient preference

8. AAFP/ACP Recommendations on 1st diagnosed episode of AF • Rate control with chronic anticoagulation is for the majority • Beta blockers and calcium channel blockers for rate control • Anticoagulation – warfarin • For rhythm control – both DC and pharmacologic cardioversion appropriate • After cardioversion – typically no antiarrythmics

9. Rhythm Control • Synchronized DC cardioversion and pharmacologic cardioversion • > 48 hours, or <48 hrs with mitral stenosis or hx of emboli – you must anticoagulate • 3-4 weeks of INR at 2-3 • Unless – TEE has excluded thrombi • If unstable –DC cardioversion • If stable and correction of underlying problem does not help – either choice

10. Compare Shock vs. Drugs • DC cardioversion – 75-93% successful • Depends on atrial size and duration of AF • Drugs – 30-60% successful • <7 days – dofetilide, flecainide, ibutilide, propafenone • >7 days – dofetilide

11. Maintenance of NSR Only 20-30 percent of patients stay in sinus for >1 year. Consider Antiarrythmics • Don’t in patients with AF less than 1 year, no atrial enlargement, reversible cause • Consider it in patients with high risk of recurrence • Risks generally outweigh benefits. • Amiodirone – good, but high toxicity profile, used in patients with bad heart disease (significant systolic dysfunction, hypertension with LVH) • Toxicity – pulmonary, photosensitivity, thyroid dysfxn, corneal deposits, ECG changes, Liver dysfxn

12. Rate Control • RVR causes • Symptoms and Hemodynamic Instability • Tachycardia mediated cardiomyopathy • Rate control • Achieved by slowing AV conduction (beta blockers, calcium channel blockers, dig, amio) • Digoxin only in hypotension and Heart Failure • Amiodirone – rarely but effective

13. AFFIRM trial • Heart Rate Targets – rest and exercise • Resting <80/min • 24 hr avg of <100/min and no rate >110 percent of predicted max for age • <110 beats/min in six minute walk Essential component is absence of activities during normal activities or exercise.

14. Rate vs. Rhythm control AFFIRM and RACE trials: Two conclusions • Embolic events are equal and occur with low INR levels or after warfarin stopped • Trend toward a lower incidence of the primary end point (mortality and event free survival) in rate control. There was no difference in the quality of life or functional status. ۞ Rate control is therefore preferred in all except: • Persistent symptoms, Inability to attain rate control, patient preference • Also consider cardioversion for young healthy patients and first episodes with low risk of recurrence. Antiarrythmics usually not used following cardioversion.

15. Anticoagulation during reversion to NSR • AF >48 hrs or unknown • Anticoagulate for >3 weeks, INR 2-3 • Or, TEE to eval for clots in LA Appendage – if no clots – convert. • After, anticoagulate for 4 weeks with warfarin – “stunned atrium” • Consider chronic anticoagulation for those with high risk for reversion.

16. Why chronic anticoagulation once cardioverted and NSR? • Pt’s at high risk for recurrence – asymptomatic periods of short AF – produce thrombi – then embolize (90% of recurrent episodes not noticed) • Some Pt’s with AF that is not associated with reversible cause are at high risk for emboli anyway (aortic plaque, LV systolic dysfxn)

17. Anticoagulation in Chronic AF • Stroke associated with AF is 3-5%/year without anticoagulation • Many factors determine ASA vs. warfarin • Estimated risk of stroke is determined with a CHADS2 score and therapy determined with this scale of 1-6. (CHF, HTN, Age, DM, Secondary prevention) • 0 get ASA because of 0.5%/year w/o coumadin • 1-2 intermediate risk • > or = 3 warfarin • P.S. – ASA usually added to warfarin

18. New Onset Atrial Fibrillation • ER reversion - <48 hrs, uncomplicated, low risk – convert them and get them out. • Safe and cost effective • Hospitalization Admission Indications • Rule out MI – ST elevation/depression • Treating associated medical problem • Elderly patients • Underlying heart disease with hemodynamic effects from AF or could be at risk for complication from therapy

19. New Onset Contd. • Search for cause – fixing the cause may cause reversion by itself. • If fixing a cause start heparin as an inpatient and bridge to coumadin for 3-4 weeks in anticpation of cardioversion if pt. doesn’t spontaneously convert • Indications for immediate cardioversion • Active ischemia • Hypotension • Severe HF

20. New Onset contd. • Start rate control – mild to moderate symptoms • Beta blockers, Calcium channel blockers ( verapamil and diltiazem), and digoxin • Digoxin good for 2nd line or in HF • Can use both BB and Calcium Ch. Blocker together. • Elective Cardioversion • Immediate – if less than 48 hrs and no cardiac abnormalities • Delayed – anticoagulate first 4 weeks. • Duration >48 hrs, assoc. mitral valve disease or Cardiomyopathy/HF, prior stroke/TIA