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ATRIAL FIBRILLATIONClassification (JACC 2006;48:e149)• Paroxysmal (self-terminating) vs. persistent (sustained 7 d) vs. permanent (typically1 y and when cardioversion has failed or is foregone)• Valvular (rheumatic MV disease, prosthetic valve, or valve repair) vs. nonvalvular• Lone AF age 60 y and w/o clinical or echo evidence of cardiac disease (including HTN)Epidemiology and Etiologies (Annals 2008;149:ITC5-2)• 1% of population has recurrent AF (8% of elderly); mean age at presentation 75 y• Acute (up to 50% w/o identifiable cause)Cardiac: CHF, myo/pericarditis, ischemia/MI, hypertensive crisis, cardiac surgeryPulmonary: acute pulmonary disease or hypoxia (eg, COPD flare, pneumonia), PEMetabolic: high catecholamine states (stress, infection, postop, pheo), thyrotoxicosisDrugs: alcohol (“holiday heart”), cocaine, amphetamines, theophylline, caffeineNeurogenic: subarachnoid hemorrhage, ischemic stroke• Chronic: c age, HTN, ischemia, valve dis. (MV,TV,AoV), CMP, hyperthyroidism, obesityPathophysiology (NEJM 1998;339:659; & Circ 1995;92:1954)• Commonly originates from ectopic foci in atrial “sleeves” in the pulmonary veins• Loss of atrial contraction S HF; LA stasis S thromboemboli; tachycardia S CMPEvaluation• H&P, ECG, CXR, echo (LA size, ? thrombus, valves, LV fxn, pericardium), K, Mg, FOBTbefore anticoag,TFTs, ? r/o ischemia (AF unlikely due to ischemia in absence of other sx)Figure 1-5 Approach to acute AFAF 1-35New or Recent-Onset AFstableunstableUrgentcardioversionSpont. cardioversion(occurs w/in 24 hrs in 50-67% acute AF)1. Rate Control 2. Anticoagulate3. CardiovertβB or CCB(see Table)IV UFH if admitting & cardiovertingo/w oral anticoagAF 48 hrs (or unknown)or high risk of strokeCardioversion(electrical and/or pharmacologic)TEE+ LAthromb.reEmpiric oralanticoag × ≥3 wks− LAthromb.Cardioversion oralanticoag × ≥4–12 wks↓(Adapted from NEJM 2004;351:2408; & JACC 2006;48:e149)Rate Control for AF (Goal HR 60–80, 90–115 with exertion)Agent Acute (IV) Maint. (PO) CommentsVerapamil5–10 mg over 2 120–360 mg/d T BP (Rx w/ Ca gluc)may repeat in 30 in divided doses Watch for CHF0.25 mg/kg over 2 120–360 mg/d Preferred if COPDDiltiazem may repeat after 15 in divided doses Can c dig levels5–15 mg/h infusionMetoprolol5 mg over 2may repeat q5 325–100 mg bidor tidT BP (Rx w/ glucagon)Watch for CHF &Propranolol1 mg q2 80–240 mg/d in bronchospasmdivided doses Preferred if CADDigoxin 0.25 mg q2h 0.125–0.375 mg Consider in HF or low BP(takes hrs) up to 1.5 mg qd (adj for CrCl) Poor exertional HR ctrlAmiodarone 150 mg over 10 S 0.5–1 mg/minB CCBIV B, CCB, and digoxin contraindicated if evidence of WPW (.e., pre-excitation or WCT) since mayfacilitate conduction down accessory pathway leading to VF; ∴ procainamide 1st line Rx