Atrial fibrillation
Posted by dkwinter

     A common complication of CABG
     Absence of P waves
     Irregularly irregular rhythm
          Paroxysmal (<7 days duration)
          Persistent (>7 days duration)
          Permanent (>1 year)
     Lone AF is AF (in any category) without structural heart disease and generally occurs in patients aged <60 years.
     Embolic stroke (up to 5 events per 100 patient life-years). Risk is greater in presence of hx of previous stroke, heart failure, valvular disease, diabetes, or hypertension.
     Ischemic heart disease
     Thrombus formation
     Arterial embolism
Tx, if first episode
     Identify and correct cause
     Convert to sinus rhythm (ideally)
     Admit to telemetry
     Control rate with 
          1. Cardizem (IV bolus; if a-fib persists, start drip)

               20 mg IV over 2 minutes, may repeat after 30 minutes. Once rate <=110 then convert to oral IR dosing q6h, keep on q6h to titrate then convert to extended release

                    Note: it is perfectly fine to treat with a non-dihydropyridine CCB (e.g. Diltiazem) even if recently/simultaneously treated with a betablocker (PO or IV)
          2. Metoprolol
           if 1 and 2 fail, use
     Consult cardiology
          Cardioversion may be attempted, but not before stabilization with rate control.
               Amiodarone can be used to convert to sinus rhythm. It has roughly the same efficacy as electrical cardioversion.

                    Sample loading dose regimen: Amiodarone 400mg po q12h x 8/7 then 200 mg po daily x 4/52. Remember to also anticoagulate
     If hemodynamically unstable
          Immediate synchronized DC cardioversion is indicated, with success rate of approximately 90% for recent-onset AF
          Cardioversion is favored over pharmacologic cardioversion due to its higher success rate and reduced likelihood of inducing an arrhythmia
     Stroke risk is decreased by
          Anticoagulation (See CHADS2) PLUS
          Rhythm control OR
          Rate control
          Rate control plus anticoagulation is preferred in most patients
          If a patient is asymptomatic, without tachycardia, provide anticoagulation but not rate control
     Rate control
          Amiodarone (does both)
          Calcium channel blockers
          Beta blockers
     Rhythm control
          Amiodarone (does both)
Tx (if WPW)
     AVOID AV nodal blockers like beta-blockers, calcium channel blockers, digoxin, and adenosine because they can cause increased conductance through the accessory pathway