Converting Atrial Fibrillation to
NSR
Pills or Electrical Thrills
Peter Holzberger MD
www.mediclicks.net
Background
• Atrial fibrillation is the most common
sustained arrhythmia
• Affects 2 million Americans
• 6% over the age of 65 experience it
• Responsible for 15% strokes
– Benjamin E: Epidemiology of Atrial Fibrillation. In Falk RH, Podrid PJ, eds:Atrial
Fibrillation: Mechanisms and Management. 2nd Ed, Lippincott-Raven Press, New
York 1997, pp.1-22.
Symptoms
•
•
•
•
Inappropriate heart rate response
Irregular rate
Loss of atrial systolic function
Thromboembolism
Choices for Immediate Treatment
• Anticoagulation and Rate Control
• Or
• Conversion to NSR
NSR-Pills Or Electrical Thrills
• Pills
– Placebo
– Single Dose Antiarrhythmic Treatment
– Ibutilide
• Electrical Thrills
– Traditional External Cardioversion
– Double External Cardioversion
– Biphasic Cardioversion
Choices
• 40 yr old healthy female with 6 hrs of
palpitations. First time ever.
• Found in atrial fib. Rate slowed with IV
lopressor, and patient feels much better.
• ED evaluation entirely normal
• Next step is ?
Choices
• A) DC Cardioversion
• B) P.O. Propafenone
• C) Discharge on p.o. lopressor and
revaluate next day
• D) Admit for further workup and treatment
Predictors of Conversion to NSR
• Duration of atrial fib
– <24 hrs spontaneous conversion in up to 66%
• Underlying cardiac function
• Underlying cardiac disease
• Age
Pills - Placebo
• Conversion of recent onset paroxysmal
atrial fibrillation to normal sinus rhythm:
The effect of no treatment and high-dose
amiodarone. A randomized, placebo
controlled study
– 100 patients PAF (<48 hrs)
– IV Amiodarone (3 gms) vs. IV Placebo
– Cotter et al,.Eur Heart J Dec 1999; 20(24):1833-42
Placebo
Conversion (%)
100
90
80
70
60
50
40
30
20
10
0
P=0.0017
92
64
IV amiodarone
IV Placebo
24 hrs
– Cotter et al,.Eur Heart J Dec 1999; 20(24):1833-42
Choices
• 45 yr old on Coumadin for recent DVT
presents with several day history of
palpitations.
• INR has been therapeutic for several
months
• Rate is controlled but still feels poorly
• Evaluation entirely unremarkable
• What next?
Choices
• A) DC Cardioversion
• B) P.O. Propafenone
• C) Discharge on p.o. lopressor and
revaluate next day
• D) Admit for further workup and treatment
Pills - Single Dose Rx
– Boriani et al, Pacing Clin Electrophys Nov 1998; Vol.21 Part II, 2470-74
Single Dose
• 417 patients with AF < 8 days
• Randomized to
– Placebo
– IV Amiodarone 5mg/kg bolus followed by 1.8
gms/24hrs
– IV Propafenone
– PO Propafenone 600 mg
– PO Flecainide 300 mg
– Boriani et al, Pacing Clin Electrophys Nov 1998; Vol.21 Part II, 2470-74
Single Dose
100
80
Placebo
IV Amio
IV Prop
PO Prop
PO Flec
60
40
20
0
SR≤1 hr
SR≤3hr
SR≤8hr
– Boriani et al, Pacing Clin Electrophys Nov 1998; Vol.21 Part II, 2470-2474
Choices
• 45 yr old female with several week history
of worsening SOB, no palpitations
• Exam reveals, mild CHF, A fib rate 140,
Echo EF 35%-global hypo
• What next?
Choices
• A) DC cardioversion
• B) p.o. Propafenone
• C) Discharge on p.o. lopressor and
revaluate next day
• D) Admit for further workup and treatment
Anticoagulation Prior to
Conversion to NSR
• At least 3 weeks Therapeutic INR >2.0
• Unless arrhythmia is less than 48 hours in duration
– Even then heparin has been advocated in high embolic
risk patients
• Mitral stenosis, CHF, previous emboli
–
Chest. Sixth ACCP Consensus Conference on Antithrombotic Therapy Vol. 119(1) Suppl. Jan
2001 194S-206S
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TEE Prior to Conversion to NSR
Thrombus
Pills (sort of) -Ibutilide
Pills (sort of) -Ibutilide
Pills (sort of) -Ibutilide
Ibutilide
– Stambler et al, Circulation October 1996; Vol 94, No 7, 1613-21
Ibutilide
• 266 patients (3 hrs to 45 days)
– 133 with atrial flutter
– 133 with atrial fibrillation
• Randomized to
– Placebo/Placebo
– 1mg/0.5mg
– 1mg/1mg
– Stambler et al, Circulation October 1996; Vol 94, No 7,1613-21
Ibutilide
– Stambler et al, Circulation October 1996; Vol 94, No 7,1613-21
Ibutilide
• Proarrhythmia
– PMVT developed in 8.3%
• Sustained PMVT 1.7%
– MMVT developed in 4%
• QTc prolonged an average of 63 msec.
• No hemodynamic effects
– Stambler et al, Circulation October 1996; Vol 94, No 7,1613-21
Ibutilide
• Contraindications
–
–
–
–
–
–
Hx of Torsades
QTc > 440
K< 4.0 mEq/L
Concomitant Type 1 or III drug
HR <60
Severe LV dysfunction (EF < 30%)
Ibutilide
• Key Points
– Close monitoring during infusion
• For NSR, PMVT (3 beats), QTc >600msec,
conduction or hemodynamic problems
– Monitor post infusion for at least 4 hours or
until QTc returns to baseline
– (longer with hepatic dysfunction)
– Trained personnel, defibrillator, Code Cart and
IV magnesium should be present
Pills Or Electrical Thrills
• Pills
– Placebo
– Single Dose Antiarrhythmic Treatment
– Ibutilide
• Electrical Thrills
– Traditional External Cardioversion
– Double External Cardioversion
– Biphasic Cardioversion
Electrical Thrills - DC
• Used for conversion of atrial fib by Dr
Bernard Lown in the 1960’s
– 94% of 456 cases of atrial fib
• Overall efficacy felt to be about 85%
• Use of high energy (360J) associated with
skin burns and possible myocardial stunning
DC Cardioversion
• Efficacy dependent on
–
–
–
–
Paddle size and position
Transthoracic impedance
Energy Waveform
Underlying disease
Paddle Position
• Anterior/Posterior #1
Paddle Position
• Anterior/Posterior #2
Paddle Position
• Anterior/Anterior
Transthoracic Impedance
• Lowered by putting pressure on the anterior
paddle during cardioversion
Electrical Thrills - Double DC
– Saliba et al, J Am Coll Cardiol 1999; Vol.34, No 7: 2031-34
Double External Cardioversion
• Double Shock
Double External Cardioversion
• 55 patients who had all failed conventional
DC cardioversion
• 84% success rate
– 9 patients received more than one 720J
• No complications
• Saliba et al, J Am Coll Cardiol 1999; Vol.34, No 7: 2031-34
Pills and Electrical Thrills
– Oral et al, NEJM 1999, Vol. 340 No24:1849-54
Ibutilide and DC Cardioversion
• 100 consecutive patients
– 50 assigned conventional DC
– 50 pretreated with 1 mg Ibutilide
100
100
P<0.001
90
72
80
70
DC only
60
50
Ibutilide/DC
40
30
20
–10 Oral et al, NEJM 1999, Vol. 340 No24:1849-54
0
% Success
Ibutilide and DC Cardioversion
• 20% treated with Ibutilide converted
without DC
• 14 patients who did not convert with DC
alone were then pretreated with Ibutilide
– None converted with drug alone
– All converted with DC
• Oral et al, NEJM 1999, Vol. 340 No24:1849-54
Electrical Thrills
Damped Biphasic
Biphasic - AF
• 165 patients randomized to monophasic vs.
biphasic shocks
– Stepped approach
• Biphasic: 70,120,150,170
• Monophasic:100,200,300,360
– Mittal et al, Circulation March 2000,Vol.101(11): 1282-87
Biphasic - AF
– Mittal et al, Circulation March 2000,Vol.101(11): 1282-87
Conclusion
• Prior to conversion:
– A fib less than 48 hrs or,
– Anticoagulation with an INR >2.0 for 3 weeks,
or
– TEE showing no clot at time of conversion
• Pills work about 40% of the time
• Electrical Thrills work about 90% of the
time
Conclusion
• Biphasic waveform is superior and desirable
• Ibutilide will have a role
– unable to perform anesthesia
– very effective for atrial flutter
– facilitate DC cardioversion
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