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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
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Converting Atrial Fibrillation to NSR Pills or Electrical Thrills Peter Holzberger MD
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
Pills Placebo Single Dose Antiarrhythmic Treatment Ibutilide Electrical Thrills Traditional External Cardioversion Double External Cardioversion Biphasic Cardioversion NSR-Pills Or Electrical Thrills
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
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 Pills - Placebo
Placebo • Cotter et al,.Eur Heart J Dec 1999; 20(24):1833-42 P=0.0017 Conversion (%)
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 • 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
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 Anticoagulation Prior to Conversion to NSR
TEE Prior to Conversion to NSR Thrombus
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
Efficacy dependent on Paddle size and position Transthoracic impedance Energy Waveform Underlying disease DC Cardioversion
Paddle Position • Anterior/Posterior #1
Paddle Position • Anterior/Posterior #2
Paddle Position • Anterior/Anterior
Lowered by putting pressure on the anterior paddle during cardioversion Transthoracic Impedance
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
Oral et al, NEJM 1999, Vol. 340 No24:1849-54 Pills and Electrical Thrills
Ibutilide and DC Cardioversion • 100 consecutive patients • 50 assigned conventional DC • 50 pretreated with 1 mg Ibutilide • Oral et al, NEJM 1999, Vol. 340 No24:1849-54 P<0.001
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