Transcript Evaluation of AF

Atrial Fibrillation
Andreas Stein
Robert Smith, M.D.
August 11, 2003
Definition
Atrial fibrillation/flutter is a disorder of
heart rhythm (arrhythmia) usually
with rapid heart rate, in which the
upper heart chambers (atria) are
stimulated to contract in a very
disorganized and abnormal manner.
Prevalence
• Overall prevalence 1%
• Increases with age
• Higher in men than in women
Classification
• Paroxysmal AF: less than 7 days
• Persistent AF: longer than 7 days
• Permanent AF: longer than 1 year
• Lone AF: no structural heart disease
Etiology
• AF with Heart disease complicated by the
following is most common (~80%):
– Atrial enlargement
– Elevation of atrial pressure
– Infiltration or inflammation of atria
• Lone AF (~20%):
– Electrophysiologic properties
Etiology (cont)
Common diseases underlying AF:
• Hypertension
• Coronary Heart disease / MI
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Rheumatic heart disease
Dilated cardiomyopathy
Hypertrophic cardiomyopathy
Congenital heart disease
Hyperthyroidism
Inflammation
Evaluation of AF
History and Physical Examination:
– Define symptoms associated with AF
– Clinical type or “pattern” (Classification)
– Onset or date of discovery
– Frequency and Duration
– Precipitating causes and modes of
termination
– Response to drug therapy
– Presence of heart disease or potentially
reversible causes
Evaluation of AF (cont)
• Electrocardiogram:
– Presence of AF
– Left ventricular hypertrophy
– Preexcitation
– Bundle branch block
– Prior MI
– Measure important intervals such as: RR,
QRS and QT
Evaluation of AF (cont)
• Echocardiogram
– Transthoracic Echocardiogram:
• size and function of atria and ventricles
• low sensitivity for thrombi
– Transesophageal Echocardiogram:
• High sensitivity for atrial thrombi
• Need of anticoagulation prior to cardioversion
• Assessment for Hyperthyroidism
– TSH measurement
General Treatment Issues
• Rhythm control:
– reversion to normal sinus rhythm
• Rate control:
– administration of medications to control the ventricular
rate in chronic AF
• Choosing between rhythm and rate control
• Prevention of systemic embolization
Rhythm Control
• Synchronized External DC Cardioversion
– hemodynamically stable and unstable patients
– ~80% overall success rate
• Pharmacologic Cardioversion
– hemodynamically stable patients
– Class IA ; IC ; III anti arrhythmic drugs
– ~60% overall success rate
Rule out atrial thrombi by TEE
or anticoagulation for 3 – 4 week
Drugs for AF <7 Days
Drugs for AF >7 Days
Maintenance of NSR
• ~20% maintain in NSR without chronic antiarrhythmic therapy
• Class IA, IC, and III drugs:
– Flecainide  minimal heart disease
– Amiodarone  reduced EF
– Sotalol  coronary heart disease
• Alternative methods:
– ablative procedures
– pacing
– insertion of an implantable atrial defibrillator
Maintenance of NSR
Rate control in chronic AF
Slowing AV nodal conduction:
• beta blocker
• calcium channel blocker
• digoxin
Rhythm Control vs. Rate Control
• Embolic events occur with equal frequency
in rate control and rhythm control
strategies
• Almost significant trend toward a lower
incidence of the primary end point with
rate control
Prevention of Systemic
Embolization
• Anticoagulation during restoration of NSR
– AF > 48 hours 3 to 4 weeks of warfarin prior to
and after cardioversion
– recommended target INR is 2.5
• Anticoagulation in chronic AF
– Aspirin: low risk patients (<65y; no risk factors)
– Warfarin: other than low risk patients
~70% reduction of stroke