Atrial FIbrillation

1. Atrial FIbrillation David W Kabel MD, FACC September 4, 2013

2. AF-Scope of the Problem • 2.7 million Americans have atrial fibrillation • Numbers are expected to rise in the future • Aging population • More chronic cardiac conditions • Better detection through long term monitoring • Event monitors, pacemakers, implantable monitors • Costs continue to rise • Annual cost is $7-10 billion per year and rising • Admissions for AF are up 66% in past 20 years

6. AF-Prevalence by Decade • Overall prevalence-1% • <65 3-5% • <80 10%+ • 1.5 times higher in men • 2 times higher in caucasians

7. AF-Associated Conditions • Cardiac risk factors • Hypertension • ASHD and PVD • CHF • Cardiac surgery (25-30% postop) • Non-cardiac risk factors • Family history of AF • Diabetes and metabolic syndrome • Obstructive sleep apnea • Obesity • Psychological stress • COPD • Hyperthyroidism • Tall stature • Inflammatory conditions (elevated CRP) • Modifiable risk factors • Smoking • ETOH >3 drinks per day

9. “Lone” Atrial Fibrillation • AF in absence of underlying risk factors • 12-20% of all AF patients • 45% of AF in younger patients

10. Classification of AF

11. AF-History and Physical Exam • Presence and nature of symptoms • Clinical type • Onset of first attack or date of discovery • Frequency, duration, precipitating factors, and mode of termination • Response to any medications previously given • Presence of underlying heart disease or other reversible conditions (hyperthyroidism, etc)

12. AF-EKG • Confirm presence of AF • LVH • P wave morphology • Pre-excitation • Previous MI • Left or Right BBB • Other atrial arrhythmias • Measure PR, QRS, and QT intervals in conjunction with anti-arrhythmic therapy

13. AF-Transthoracic Echo • Valvular disease • LA and RA atrial size • LV size and function • LVH • Right sided pressures (pulmonary hypertension) • LA thrombus(low sensitivity) • Pericardial disease

14. AF-Initial Workup • Chest X-ray • Cardiomegaly • Pulmonary disease • Blood work • Thyroid functions • BMP • Hepatic profile • CRP? • CBC

15. AF-Additional Testing • May be indicated in some circumstances • Stress testing • If AF is exercise induced • To assess rate control • Holter monitor, event monitor • If diagnosis is in question • To assess rate control • TEE • Looking for LAA thrombus • To guide cardioversion • EP studies • Wide complex tachycardia • Pulmonary vein isolation • AV node ablation and pacemaker • Sleep study-especially if episodes are mostly nocturnal

16. AF-Goals of Therapy • Rate control • Most important initial strategy • Prevention of CHF (tachycardia induced cardiomyopathy) • Restoration of sinus rhythm (rhythm control) • May be initial strategy in some patients • Prevention of thromboembolism(TE)

24. AF-DC Cardioversion-Indications • Class I • Symptoms or signs of ischemia, hypotension, angina or heart failure • Pre-excitation syndrome with extreme tachycardia and hypotension • Symptoms are unacceptable to the patient • Class IIa • Part of long term management strategy • Patient preference in cases of infrequent episodes of AF • Class III • Relatively short intervals between episodes of AF • Presence of digitalis toxicity or hypokalemia

25. Anticoagulation Prior to DCC • Class I • Duration >48 hrs or unknown-Oral anticoagulation (OAC) for 3 weeks before and 4 weeks after DCC • Duration >48 hrs and hemodynamically unstable-IV heparin followed by OAC for 4 weeks. Role of LMWH is uncertain • Duration <48 hrs-DCC without prior OAC, followed byOAC post-procedure depending upon TE risk • Class IIa • Duration <48 hrs-OAC prior dependent upon risk • TEE guided-Proceed if no LAA thrombus-OAC for 4 weeks post DCC. Limited date on LMWH

26. AF-Non-Pharmacological Therapies • AV node ablation with pacemaker • Indicated in persistent or permanent AF when ventricular rate cannot be controlled medically or patient is intolerant to rate control medications • Cryoablation of AV node • Patient becomes pacemaker dependent • Pulmonary vein isolation-cryoablation • Right sided approach across atrial septum to LA. • 4 pulmonary veins are identified and cryoablation occurs in circular pattern around pulmonary vein orifices • Rare complication of PV stenosis leading to PHT • Initial success rate of 80-90% • Repeat PVI common

27. AF-Non-Pharmacological Therapies • Surgical Maze Procedure • Series of incisions inside the left atrium to redirect and organize electrical impulses -done on cardiopulmonary bypass • Usually done in conjunction with mitral valve surgery or other cardiac surgeries • May be done as stand alone procedure in intractable cases who are highly symptomatic

29. AF-Prevention of Thromboembolism(TE) • Risk Stratification is key to decision making • Must weigh risk of bleeding into the calculation • Newer anticoagulants appear “non-inferior” to warfarin for prevention of TE • “Non-valvular” AF means absence of rheumatic mitral valve disease of mechanical prosthesis

30. AF-Prevention of Thromboembolism • Estimates are that only 50-60% of AF patients at risk for TE are on OAC • Reasons cited include risk of bleeding and risk of falls. • Patients at highest risk of bleeding and falls are also at highest risk of TE

37. Swedish AF Cohort Study • 182,000 patients through national registry • Compared risk of ischemic stroke without OAC vs risk of intracranial hemorrhage while taking OAC • Used CHADS-VASC and HAS-BLED scoring systems

38. Swedish AF Cohort Study

39. AF-Swedish AF Cohort Study

40. AF-Donze, etal AJM-Risk of Falls and Major Bleeds in Patients on OAC

41. AF-Donze, etal

42. AF-Donze, etal

43. AF-Donze, etal

44. ATRIA Study • Anticoagulation and Risk Factors in AF Cohort • Kaiser Permanente of Northern California database • 13,559 adults with AF followed a mean of 6 years • Followed patients taking and not taking OAC

45. ATRIA-Risk-Benefit Calculation

48. ATRIA-Benefit by CHADS2 Score