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PresentationA 28 yo male with no prior cardiac history
presents complaining of palpitations,
lightheadedness and decreased exercise tolerancefor the last 6 hours. The symptoms came onsuddenly at 4 AM, awakening him from sleep.He had been up the night before drinking heavily.
No significant medical history.No medicationsNo smokingOccasional binge drinking
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BP 100/60, Pulse 140 and irregularlyirregular, RR 18Rest of exam is normal, except heartsounds, which are irregularly irregular withvariable intensity S1.
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The lifetime risks at age 40 years for developing the disorder were 26%(95% CI 2427%) for men and 23% (2124%) for women
1st detected vs. recurrent (>2 episodes)
Lone AF = age 7d) vs. permanent (>1yr when cardioversion has failed)
Acute: due to cardiac (CHF, pericarditis, etc), pulmonary (PE, pneumonia,etc), metabolic ( high catecholamine states, thyrotoxicosis) or drugs/alcohol
Chronic: due to age, HTN, ischemia, thyroid, obesity, valvular disease
Atrial Fibrillation
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Risk Factors for AtrialFibrillation (2.3 Million Patients)
Age (3.8% of U.S. population > 60; 9.0 % > 80)Hypertension
Coronary artery diseaseCardiomyopathyValvular disease (primarily mitral)Hyperthyroidism
Excessive alcohol intakePulmonary disorders including pulmonary embolismAfter cardiac surgeryMyocarditis or PericarditisObstructive sleep apnea
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Work-Up
H&PECG (verify the presence of Afib)
CXR (look for pneumonia, CHF, pulmonarycause)Thyroid Function Tests (TFTs)Echocardiogram (check PA pressures, leftventricular function, left atrial size, valvular disease)Consider stress test to test if ischemic/exerciseinduced Afib
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Atrial Fibrillation:Acute Management
Control ventricular rate (which can be quite fast [180-200] in theyoung healthy patient):
F blockers: especially effective in post-op/high catecholaminestates
Ca 2+ blockers: quicker onset v. beta blockers
Digoxin: useful in hypotensive patients
Combinations of the above
Watch for hypotension
Expect spontaneous cardioversion in 50-67% with acute AF w/in24 hrs
Target
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Atrial Fibrillation:Acute Management
Consider urgent cardioversion (drugs or electrical) if patient is unstable
Potassium channel blockers
Ibutilide
Dofetilide
Sodium channel blockers
Propofenone
Flecainide
Amiodarone
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Atrial Fibrillation: Acute ManagementConsider cardioversion (drugs or electrical)
Potassium channel blockers (prolong action potential)
Ibutilide (intravenous, feared to cause polymorphic ventricular tachycardia)
Dofetilide (oral, may also cause polymorphic VT)
Sotalol (do not use in patients with low EF)
Sodium channel blockers
Propofenone (oral, can cause ventricular arrhythmias)
Flecainide (oral, this drug may also cause ventricular arrhythmias,shown to kill people in the CAST study)
Amiodarone (least pro-arrhythmic. Use in patients with any form of structura l heart disease inc luding CAD)
Cardioversion in pts w/1 st episode of AF or in those w/sx. If >48hrs, getTEE to r/o thrombus. If high risk patient (mitra l stenosis, prior embo li),anti-coagu late for 3 wks before attempting cardioversion/INR >2
Increase like lihood of success if
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How do you maintain sinusrhythm?
First question: do you need to? Answer: Maybe not, unless patient is hard to rate
control or symptomatic when in AF. Also like to tryif its the first episode.
Second question: what can you use if everythingis deadly? Beta blockers help and control rate if return to AF. Amiodarone seems safest long term (low dose) in
patients with other cardiac disease, but agents like propofanone and flecainide are preferred if theresno other cardiac disease whatsoever.
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AFFIRM Trial: No advantage for rhythm control
Rhythm control group had 6 times as manyepisodes of polymorphic VT.Rhythm control group had twice as much
bradycardia.Strokes occurred in both the rate and
rhythm control groups
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Stroke in AF5% to 6% annual risk of embolic strokeHigher in patients with: Prior stroke Diabetes Hypertension history Heart failure history
Age > 60>10% in the setting of rheumatic valvular disease.Lifelong warfarin reduces risk substantially evens/p cardioversion
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Preventing ThromboembolicStroke
Do not cardiovert if patient known to be in atrialfibrillation for longer than 48 hours without first
getting transesophageal echocardiogram (TEE) toverify there is no clot.If uncertain of timing of onset, dont take achance: get a TEE.Lifelong warfarin if in high risk group.Aspirin sufficient in the low risk group.Use the CHADS2 risk score to determine need for
warfarin in non-valvular AF.
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CHADS2 Score for Stroke Risk in non-valvular Atrial Fibrillation
Condition Points
C ongestive heart failure (any history) 1
H ypertension (prior history) 1
Age 75 1
D iabetes mellitus 1
Secondary prevention in patients with a prior ischemicstroke, transient ischemic attack, systemic embolic event
2
Score = 0 Aspirin
Score = 1-2 Individualize ( W arfarin if S)
Score = 3 or greater W arfarin
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Stroke Risk W hether the atrial fibrillation is chronic,intermittent (so-called paroxysmal atrialfibrillation), or requires medication for rhythm control, the risk of stroke isincreased and justifies the use of
anticoagulation90% of pts have asymptomatic afib,90%>48hrs, always risk of thrombus!
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If other treatments don't work:Ablate the AV node.Place a permanent pacemaker.Not an ideal scenario: Lack of physiological rate dependence Foreign body forever Pulse generator changes Hard to do an MRI
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W hat about our patient?
He received 15 mg of metoprolol IV push in3 divided doses over 15 minutes.His heart rate dropped to 110 and he felt much
better.Echo and CXR were normal. He had no signs or symptoms of hyperthyroidism.He was given 600 mg oral propofanone, andconverted to sinus rhythm 2 hours later. After another 6 hours of observation for arrhythmias, hewas discharged home on one 325 mg aspirin a day.He has had no further episodes Lone AF
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