CASE CONFERENCE

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CASE CONFERENCE

• May 26, 2005

Greg Ginsburg, M.D.
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Our Topic

• Management of
• New Onset
• Atrial Fibrillation

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coming attractions

• Basics of A-fib
• Evaluation of A-Fib
• minimal evaluation
• additional evaluation
• Approach to Treatment
• rate, anticoagulation, rhythm
• cardioversion

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First, a few basics about A-fib
A-fib is the most common arrhythmia that requires
treatment prevalence 4 of people gt 60 years
old prevalence 9 of people gt 80 years old May
be asymptomatic (20 of newly diagnosed cases)
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The Danger of A-fib

• Stroke secondary to thromboembolism emanating
  from left atrial appendage
• Chronic vs. paroxysmal similar risk of stroke
• Annual rate of CVA in untreated a-fib approx 3
• Increased relative risk (1.3 to 2.0) of death
  independent of other risk factors

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Causes of Atrial Fibrillation

• lone A-fib no identifiable explanation (3-30
  cases)
• changes in autonomic tone or atrial wall tension
• (i.e. postprandial high vagal tone
  stress-induced sympathetic tone)
• ? often associated with cardiovascular dz
• (HTN, CAD, cardiomyopathy, valvular dz,
  pericarditis)
• ? other risk factors
• - Excessive EtOH, food, caffeine intake
• - Hyperthyroidism
• - Pulmonary disorders (including PE)
• - ?obstructive sleep apnea
• - recent cardiothoracic surgery
• - genetic/familial factors

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Evaluation of New Onset A-Fib
ACC/AHA/ESC GUIDELINES FOR THE MANAGEMENT OF
PATIENTS WITH ATRIAL FIBRILLATION (2001)
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minimal evaluation

• Clinical History
• Physical Exam
• 12 lead EKG
• Chest X-Ray
• Thyroid function tests
• Transthoracic ECHO

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additional evaluation

• Exercise stress test
• Electrophysiological study
• Transesophageal Echocardiography
• Ambulatory Holter/Event monitor

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minimal evaluation

• (If pt is hemodynamically stable!...)

identify any associated conditions/causes, presen
ce/duration of symptoms? angina? ( palpitations,
dyspnea, fatigue, pre/syncope)
Clinical History Physical Exam 12 lead
EKG Chest X-Ray Thyroid fnx tests Transthoracic
ECHO

• focus on cardiac and pulmonary exam

verify a-fib, ?prexcitation sydnromes (no
p-waves! r/o MAT, etc.)
focus on cardiac or pulmonary pathology
rule out hyperthyroidism
normal vs. impaired heart, valvular function
(especially mitral), chamber size/hypertrophy,
pericardial dz (NOT to be used to r/o LA thrombus)
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additional evaluation

• obtain if ischemia is suspected,
• evaluate for symptoms,
• assess heart rate response

Exercise stress test EP study TEE
holter/event monitor

• define mechanism of a-fib,
• seek sites for ablation,
• assist selection of pts for pacemaker

screen for left atrial thrombus (found in
5-15 of patients), guide cardioversion
evaluate heart rate control, clarify type of
arrhythmia(s) if in doubt
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Approach to Treatment
RATE Control of ventricular rate
ANTICOAGULATION Assess need for anticoagulation
RHYTHM Assess need for, timing of, and method of
restoring sinus rhythm
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Rhythm
Rate
Anticoagulation

• Goals
• ventricular rate 60-80 at rest
• ventricular rate 90-115 during exercise
• Medical rx
• ß-Blockers
• calcium channel blockers
• digoxin
• Surgical Rx
• pacemaker (i.e. for pauses, sick sinus syndome)

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Rate Control
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Rhythm
Rate
Anticoagulation

• Goals
• balance risk of stroke vs. risks of
  anticoagulation
• INR in range 2.0 3.0
• Patient selection
• consider pts risk of stroke
• risk factors include
• CHF, HTN, age, DM, CAD
• hx thromboembolism, TIAs, prior CVAs

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benefits of anticoagulation
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Rhythm
Rate
Anticoagulation

• Goals
• convert a-fib to NSR or maintain NSR in pt w/ PAF
• antiarrthymics drugs and/or DC cardioversion
• Caution
• antiarrhythmic drugs and DC cardioversion may
  entail serious side effects and complications
• evidence suggests rate control strategy similar
  to rhythm control strategy with regard to quality
  of life and cardiovascular end points, including
  death.
• (possibly fewer symptoms better hemodynamics)

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Rhythm
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Framework for Treatment
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Cardioversion for new A-fib

• indications
• lt48 hours duration
• hemodynamically unstable
• a-fib due to acute self-limited condition
• (i.e. pneumonia, or s/p cardiothoracic surgery)
• pt symptomatic despite rate control
• contraindications to rate/anticoagulation meds
• DC cardioversion
• 67-94 success rate
• risks of sedation/analgesia/airway management
• potentially pro-arrthythmic (shock in syncronized
  mode)
• consider anti-arrhythmic medication to improve
  success rate

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Cardioversion
A-fib lt 48 hours A-fib gt 48 hours or unkown
- may use antiarrthymic meds - may use DC cardioversion - do not use antiarrthymics - do not use DC cardioversion
- may use antiarrthymic meds - may use DC cardioversion but if pt is hemodynamically unstable, then may proceed to immediate cardioverison if time allows - IV heparin TEE - cardioversion within 24hrs - then 4 wks anticoagulation
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Obtain TEE before cardioversion?
Advantages Disadvantages
- TEE detects LA appendage thrombi, sparing those pts from cardioversion and possible CVA - in pts without thrombi, prompt cardioversion shortens anticoagulation period and thus reduces bleeding complications - may limit repeated outpatient visits for INR monitoring - cardioversion may be more successful when done sooner rather than later - lack of definitive data and guidelines re pt selection for TEE - ?rate of false positives and (more importantly) false negatives - requires expensive equipment and highly-skilled personnel - requires sedation for pt comfort, with associated airway management risks
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SUMMARY
- basics of a-fib
- evaluation minimal and additional
- approach to treatment rate, anticoagulation,
rhythm cardioversion
www.acc.org (ACC/AHA/ESC Guidelines for
Management of A-fib) www.nejm.org (Richard Page,
U.Wash 2004 Newly Diagnosed A-fib)
Thank you Ken Davison Stacey Remchuck Wilton
Levine
THE END