Atrial Fibrillation. Epidemiology. Goals 11/12/2012. Faithful marker for age and underlying cardiopulmonary disease

Transcription

1 Atrial Fibrillation Goals the emerging epidemic Rate Control Thromboembolism and anticoagulation Cardioversion: When, How, and Why 1st time AF < 48hr 1st time AF > 48hr PAF < 48 hr. PAF > 48 hr. Eric R. Snoey, MD Alameda County Medical Center Disposition: To admit or not to admit Chronic AF WPW + AF 1 2 Epidemiology Faithful marker for age and underlying cardiopulmonary disease % of general population, but 10% > 75yo 1 in 4 Americans > 40 yr will experience A-fib in their lifetime* 80% have valvular, DCM, or HTN heart disease Lone AF (no known cause) = ~ 3% of cases *Framingham data 4 1

2 Pathophysiology View AF in the context of the underlying disease process Thromboembolism 4 X increase over general population Rate varies from 1.5%/yr to 17%/yr depending on age and other risk factors Cardiomyopathy Loss of atrial kick hypotension DCM tachycardia related AF with Rapid Ventricular Response Instability = CP, Hypotension, Pulm Edema, Neuro deficits Stable or Unstable? 5 6 AF with RVR Stable Rate Control Digoxin Traditional but largely discredited due to: Slow onset Long half-life Failure to control rate in ED (high sympathetic tone)* Best as outpatient rate-control agent in sedentary patients with CHF Digoxin Diltiazem Verapamil Beta blocker 7 * Falk et al, Rawles et al A J Card 8 2

3 Diltiazem Verapamil/Beta Blockers CA channel blocker excellent AF rate control properties Fast onset (~ 5-10 minutes) Mixed AV blockade and peripheral vasodilation Effective but significantly more hypotension due to neg inotropic effects Safe even in severe LV dysfunction * Across the board improvement in Cardiovascular markers: BP, CO, Wedge Caution in patients with low BP or LV dysfunction *Heywood et al A J Card Cardioversion.. rules of engagement Peri-cardioversion Anticoagulation How, When and Whether of cardioversion: 10 Controversial Subject to many competing issues Anticoagulation Uncoordinated contraction of atria leads to clot formation Huge risk of embolism regardless of method of conversion (6% in 1st wk) AF < 48 hr. duration Peri-cardioversion Chronic * Risk = Coumadin Tx * (unless CHF, Mitral valve dz, Hx of thromboembolism)

4 Pericardioversion Anticoagulation Strategies (if AF > 48 hrs..) Coumadin for 3 weeks, then cardioversion Followed by coumadin for 4 weeks post cardioversion or Immediate Transesophageal Echo, Heparin (or LMWH), then cardioversion* Followed by 4 weeks of coumadin *Acute I & II trial 13 DC Cardioversion Conscious sedation Cardioversion Begin 100 J (< 2days), 150J (>2 days) Pharmacologic Technique Same (coagulation) rules apply.. Antiarrhythmic agents (AAA) differ wildly in terms of indications/risks/side effects Little difference in efficacy Meta analysis (91 trials): similar conversion rates among all classes ~ 50-70% of new onset AF, ~ 30 % of chronic AF 14 (Traditional) AAA classes Next wave Class Ia: Procainamide LV depressant hypotension, Torsade risk Class Ic: Propafenone, Flecainide Oral agents, contraindicated in CAD/structural heart dz Class III: Amiodarone, Ibutilide Amiodarone: Beta blocker, well tolerated in LV dysfunction, borderline BP Ibutilide: fast, effective, ~ 8% Torsade risk Avoid in low MG, Prolonged QT or simultaneous use of type Ia agents Azimilide, Vernakalant Dronedarone

5 Case 1# Vernakalant Novel agent for RAPID, IV conversion of A-fib To compete directly with Ibutilide/Amio.. ACT 1-3/AVRO trials: ~ 52% conversion of early AF (3 hrs.. 7 days) Mean time ~ 11 minutes No Torsades May be better than Amiodarone 63 yo with a 2 day sensation of palpitations and decreased exercise tolerance. He has a hx of chronic AF for which he takes Coumadin last INR = 2.5. He denies dyspnea, chest pain or syncope. PMhx: HTN, mild CHF, AF Med: Digoxin, HCTZ, Coumadin PE: 140/90, 145 irreg, 20, afebrile Recent ACT 5 trial stopped by FDA due to case of shock no approval in sight Chest: clear Cards: rapid, irreg rhythm Key points: Most AF symptoms are rate, not rhythm related!!! Why is the patient tachycardic? 19 A-fib is the Sinus Tachycardia of rhythm problems Treat the patient, not the rhythm! Key is rooting out the underlying cause 20 5

6 AF and Coumadin Rx Anticoagulation options Medical Condition Points CHADS score Risk CVA/yr CHF 1 HTN 1 Age >75 1 Diabetes 1 Prior Stroke 2 Risk of Coumadin ~ 1-2%/yr 21 Aspirin: 50% of the benefit of Coumadin Appropriate for CHADS 1 only Aspirin + Clopidogrel Inferior to Coumadin in CHADS >1 Bleeding risk same as Coumadin Coumadin: 2/3 reduction in stroke risk (vs.. placebo) 22 Coumadin: Anticoagulation Coumadin Heparin Bridging not necessary * INR = fold increased in death Oral, BID once dosing daily dosing Few drug, food interactions ROCKET No INR monitoring AF Trial (14K AF patients) Non-inferior to Coumadin in primary end points Similar overall bleeding, 1/3 fewer ICH RE-LY Trial (18K nonvalvular AF pts) Superior end point rates (150mg) vs Coumadin Similar overall bleeding rate, ~ 70% fewer ICHs

7 Case 1#: best practice Concerns GI upset - up to 30% with Dabigatran Renal excretion need dose adjustment Bleeding: no antidote... recs: Support until T1/2, maintain urine output, consider hemodialysis in renal impaired patients? PCC Rivaroxaban: complete reversal in one study of healthy volunteers with PCC Cost: ~ $8/day Work up Evaluate for underlying disease CHF, GI bleed, etc.. Therapy: Resuscitate first, then IV Diltiazem for rate control, replace Digoxin Disposition: No AF indication for admission Base decision on Non-Rhythm evaluation Case 2# 68 yo female with 4 hrs.. of palpitations typical of her A-Fib. 5 similar episodes in the past 2 years - currently on Propafenone. She had a mild asthma attack this AM (has precipitated AF in the past) Pmhx: Asthma, HTN, DM, AF Meds: Propafenone, ASA, Albuterol, HCTZ, Metformin PE: 150/90, 155, 24, afebrile Chest: mild expiratory wheezes Card: Rapid, irregular 27 Key points Treat the patient (asthma), not the rhythm Cardioversion??? Pro: < 48 hr., no anticoagulation required Con: Treat asthma and likely will spontaneously convert AFFIRM TRIAL 28 7

8 PAF & Coumadin AFFIRM Trial Rhythm control +/- coumadin vs. Simple Rate control + coumadin 4060 patients randomized Results: No difference in mortality Fewer hospitalizations and better quality of life with rate control Huge cross over from AAA side to rate control side Medical Condition Points CHF 1 HTN 1 Age >75 1 Diabetes 1 Prior Stroke 2 = COUMADIN Rx Summary: other than for symptom relief there is little 29 to support routine, aggressive efforts to maintain NSR 30 Case 3# Case 2#: best practice 55 yo with weakness and dizziness for 2 weeks thought he had the flu but it didn t get better Therapy Rate control Treat asthma Start coumadin for long term Thromboembolic prevention due to HTN and DM risk Pmhx: none Med: none Expectant mgt vs. active cardioversion Base decision on prior hx and degree of AF-related symptomatology PE: 110/80, 160, 20, afebrile Card: irreg, rapid Chest: clear Disposition: likely home DX: 1st time AF, unknown duration

9 Key points To admit or not to admit Admission should have less to do with AF than the eval of the underpinnings of AF To Cardiovert or not to Cardiovert? Most patient deserve at least one shot at NSR Pro Admit: Expedite w/u (TFTS, Echo, etc.) ED study: 2/3 of admissions for AF were justified in post hoc analysis* Permits monitoring, early cardioversion, effect of AAA (if started) Con: >48 hrs., needs formal anticoagulation 3 wks coumadin vs. TEE/Heparin/cardioversion 33 Outpt work up acceptable If rate-controlled AF tolerated, no reason to rush to conversion start coumadin, convert in 3 wks 34 *Mulcahy B,et al. Academic Emergency Medicine 1996;3: Key points: Case 4# 52 yo presents with several hours of palpitations and anxiety. He denies dyspnea, chest pain or syncope. New onset/recent onset A-fib, ( Lone A-fib ) < 48 hours / no appreciable cause Pmhx: none Meds: none Rate Control? PE: 170/110, 145, 20, 98.6 Cardioversion?: Chest: clear Card: rapid and irregular

10 Cardioversion: options Admission? Early Active cardioversion (without anticoagulation) Admission dictated by concerns for nonaf disease/co-morbidities DC vs. Ibutilide / Vernakalant* Serious AF associated symptoms: Expectant Mgt Most will convert spontaneously Recheck in 24 hours, if still in A-fib, actively cardiovert CP, CHF, syncope, CVA, hypotension Admit based on concern for these sx and diseases Key points Case 5# 28 yo male with known WPW presents after a syncopal event c/o ongoing palpitations. WPW allows for extreme rates with AF Rate control NOT an option PE: awake, alert, 100/70, 220, 20, afebrile Chest: clear Card: rapid Dilt/Beta blockers (even adenosine) contraindicated Blocks normal AV conduction pathway Risks degeneration in VT/VF Must cardiovert: DC vs. Procainamide Theoretical contraindication to amiodarone due to its Beta blocking activity

11 Summary AF is a rhythm of the elderly with heart dz AAA offer only marginal benefit if any Most patient with AF require coumadin Admission for AF is common Treat that disease, not timers the rhythm Cardioversion for 1st - done often for the is wrong reasons or those who can t tolerated AF symptoms yet may make sense to assure work up, follow up and treatment of underlying disease Case 6# Key Points 78 yo male presents with severe dyspnea, ALOC, and weakness. He carries a dx of dilated cardiomyopathy and paroxysmal AF on Amiodarone and Coumadin Small % of patients can not tolerate A-fib..period! PE: ALOC, pale in severe distress 90/50, 190, 40, afebrile Chest: florid pulmonary edema Card: rapid, irregular Patient is intolerant of rapid A-fib Immediate attempt at cardioversion If not successful rate control, inotropic support 43 Long-term: needs EP Ablation 44 11

12 THANKS! 45 12