Medical Musing of the Week: Atrial Fibrillation

Overview + Definitions

  • Most common arrhythmia
  • Increased risk with age
  • Irregularly, irregular rhythm and absent P waves on EKG
  • Valvular vs. non-valvular (valvular means that arrhythmia is being caused by some type of valve disease ie rheumatic fever or from a defect in a prosthetic valve)  Most cases are non-valvular A-Fib (you will hear that term frequently!)
  • A-Fib w/ RVR (stands for “rapid ventricular response”): This basically means that the person is not in rate controlled A-Fib and the ventricles are trying to keep up with all the beats being initiated by the atria.
  • The more days/weeks A-Fib persists the increasing likelihood that it will be permanent
  • Paroxysmal A-Fib: Self-terminating within 7 days onset.  Usually terminates <48 hours. Recurs with variable frequency.
  • Persistent A-Fib: Atrial fibrillation that fails to self-terminate within 7 days or requires medication for termination.
  • Permanent: Has persisted >12 months and cardioversion has usually been unsuccessful.  Focus shifts to rate control

Etiology + Risk Factors

  • Coronary Artery Disease
  • Congestive Heart Failure
  • Acute Coronary Syndrome
  • Hypertension
  • Pulmonary Disease (esp COPD flares)
  • Pneumonia/Infection
  • Etoh (“Holiday Heart”) –> Lots of patients will show up to the hospital around the holidays because of increase of alcohol use
  • Surgery or anything that will cause fluid shifts in the body either overload or dehydration
  • Has patient missed any doses of rate controlled medication?

Clinical Manifestations

  • Palpitations/Chest Pain
  • SOB (may have increased O2 requirement secondary to heart beating so fast patients are not perfusing appropriately and become SOB– once their HR slows the will perfuse better and O2 requirement likely subsides

Diagnosis

  • EKG
  • Troponin x3 + CKMB x1
  • CT PE study (for rule out–in hospitalized patients who have a new oxygen requirement
  • Telemetry Monitoring

Treatment

Steps to take/Questions to ask:

  • Calculate Cha2ds2 Vasc:
    • The “chads vasc” is a scale that determines an individual’s risk per year for stroke.  Based on their risk have a discussion with the patient about risks and benefits of oral anticoagulation
    • Scale includes:
      • Congestive Heart Failure
      • HTN
      • Age (2pts) >75, (1 pt) >65
      • Diabetes
      • Stroke/TIA history (2pts)
      • Vascular Disease
      • Sex (+1 if female)
  • Is the patient rate controlled?
  • New onset?
    • If rate controlled determine need for oral anticoagulation (watch providing with elderly who fall frequently)
    • If rate isn’t controlled do so with a BB
  • Is the patient rate controlled? (<110 BPM)
    • A-Fib RVR:
      • In a hospitalized patient options for treatment include IV Lopressor (may repeat for 3 doses, Cardizem 5mg +/- drip (may also repeat), Digoxin or Amiodarone bolus +/- drip
      • If low BP will want to hold off on Cardizem or Lopressor–cardizem will really drop the BP
      • Amiodarone is my go to when a patients BP is low 150mg bolus followed by a drip of 1mg/kg x6 hours, .5mg/kg for 6 hours, 400mg daily and then 200mg daily for maintenance
  • Are they hemodynamically stable?

Below is one of my favorite flow charts from UpToDate (love this source!)  This is a really good place to start to understand the treatment of A-Fib

image

 

Prognosis + Complications

  • The longer a person remains in atrial fibrillation the greater the risk it will be a permanent rhythm
  • RVR (rapid ventricular response)
    • Frequently seen in the hospital especially with CHF exacerbation, surgery (because of fluid shifts)
  • CVA/TIA
    • Because of the irregular rhythm of the atria and valves individuals with a-fib are at increased risk of developing clots on their mitral valve and throwing ot through their aortic valve and to the brain
    • Calculate chads vasc as above to determine risk

 

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