Propafenone is a currently used medicine to treat atrial fibrillation and is a mixture of two compounds, (R)-propafenone and (S)-propafenone. In this study, the investigators will randomize participants to (R)-propafenone, (S)-propafenone, or placebo.
Atrial fibrillation is a common cardiac arrhythmia that needs development of more effective medications. Propafenone is a medicine currently used to treat atrial fibrillation and is a mixture of two compounds, (R)-propafenone and (S)-propafenone. The investigators have discovered that purified (R)-propafenone may be more effective than (S)-propafenone for treatment of atrial fibrillation, and that (S)-propafenone reduces the efficacy of (R)-propafenone when administered as a mixture. This study will compare the ability of (R)-propafenone, (S)-propafenone, and placebo to suppress the induction of atrial fibrillation in participants undergoing an atrial fibrillation ablation procedure.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
193
Vanderbilt University
Nashville, Tennessee, United States
Number of Participants With Successful Induction of 30 Seconds of Atrial Fibrillation/Atrial Flutter
A rapid atrial pacing protocol was used to attempt to induce atrial fibrillation/atrial flutter. Twenty minutes after start of the study drug, participants underwent placement of a decapolar coronary sinus catheter. Pacing was performed from the proximal electrode at 20 milliamps and a pulse width of 2 ms. Bursts from the CS proximal electrode were induced to attempt atrial fibrillation.
Time frame: Twenty minutes post-dosage to end of induction protocol (approximately 10 minutes)
Number of Participants With Successful Inducibility of Atrial Fibrillation/Atrial Flutter Expressed as an Ordinal Variable Based on Stage of the Induction Protocol
Inducibility of atrial fibrillation (AF) or atrial flutter (AFL) expressed as an ordinal variable based on stage of the induction protocol. * Stage 1 measured the AV block (Wenckebach) cycle length (AVBCL), AV node effective refractory period (AVN ERP) and atrial ERP (AERP). AVN ERP and AERP were measured at drive trains (S1) of 600 ms and 450 ms. Extrastimuli (S2) were introduced starting at a coupling interval of 500ms and decremented by 10ms with each pacing train. * Stage 2 consisted of 15-beat bursts from the CS proximal electrode. The starting cycle length was 250ms, which was decremented by 10ms with each burst. A 10-second rest period was used between bursts. Step 2 was complete when 1:1 atrial capture was lost or a minimum cycle length of 180ms was reached. Stage 3 consisted of 15-second bursts. The cycle length used for the bursts was the fastest cycle length achieved during Step 2 that maintained 1:1 atrial conduction.
Time frame: Twenty minutes post-dosage to end of induction protocol (approximately 10 minutes)
Number of Participants With Successful Induction of 30 Seconds of Atrial Flutter
A rapid atrial pacing protocol was used to attempt to induce atrial flutter. Twenty minutes after start of the study drug, participants underwent placement of a decapolar coronary sinus catheter. Pacing was performed from the proximal electrode at 20 milliamps and a pulse width of 2 ms. Bursts from the CS proximal electrode were induced to attempt atrial flutter.
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Time frame: Twenty minutes post-dosage to end of induction protocol (approximately 10 minutes)