title: Comparing the efficacy and safety of a novel monophasic waveform delivered by the passive implantable atrial defibrillator with biphasic waveforms in cardioversion of atrial fibrillation.
abstract: BACKGROUND
  The passive implantable atrial defibrillator (PIAD) (with no battery or discharging capacitor and powered transcutaneously by radio-frequency energy) delivering a novel monophasic low-tilt waveform is more efficacious than the standard monophasic waveform at atrial defibrillation. Standard biphasic (STB) waveforms, however, are more efficacious and safer than monophasic waveforms. This study compared the efficacy and safety of the PIAD waveform with biphasic waveforms.
  
  
  RESULTS
  Sustained atrial fibrillation (AF) was induced by rapid atrial pacing. Cardioversion was attempted via 2 atrial defibrillation leads. The efficacy of the PIAD was compared with 3 biphasic waveforms (standard, single rounded, and double rounded) at varying voltage settings in 10 pigs. After a synchronized shock, hemodynamic changes between the PIAD, standard biphasic, and monophasic waveforms were compared at 1.5 and 3.0 J in 12 pigs. Myocardial injury (biochemical and histological) after ten 5-J PIAD shocks was compared with a no-shock group in 14 pigs. The PIAD 100-V setting was significantly more efficacious than the STB (100/-50 V: 100% [1.88+/-0.02 J] versus 90% [0.89+/-0.0 J]; P=0.025). No arrhythmic, hemodynamic, or myocardial injury was observed with the PIAD waveform.
  
  
  CONCLUSIONS
  Defibrillation with the PIAD is more efficacious than with the STB waveform and appears safe. This device could provide a more effective option for cardioversion.
authors.affiliation: Regional Medical Cardiology Centre, Royal Victoria Hospital, Grosvenor Rd, Belfast BT12 6BA, UK. gmanoharan@msn.com
authors.forename: Ganesh
authors.initials: G
authors.lastname: Manoharan
authors.forename: Noel
authors.initials: N
authors.lastname: Evans
authors.forename: Desmond
authors.initials: D
authors.lastname: Allen
authors.forename: John
authors.initials: J
authors.lastname: Anderson
authors.forename: Jennifer
authors.initials: J
authors.lastname: Adgey
mesh_terms: D000818:Animals; D002302:Cardiac Output; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000009:adverse effects / Q000379:methods*; D004867:Equipment Design; D006019:Glycolysis; D006335:Heart Injuries / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D006339:Heart Rate; D009124:Muscle Proteins / Q000032:analysis; D011827:Radiation; D013552:Swine; D016277:Ventricular Function, Left
chemical_list: D009124:Muscle Proteins