title: Worldwide clinical experience with a new dual-chamber implantable cardioverter defibrillator system.
abstract: BACKGROUND
  Management of atrial tachyarrhythmias represents a significant challenge in patients with implantable cardioverter defibrillators (ICDs). Drug therapy of these arrhythmias is limited by moderate efficacy, ventricular proarrhythmia, and drug-device interactions. This study tested the safety and efficacy of a new dual-chamber ICD to detect and treat atrial as well as ventricular tachyarrhythmias.
  
  
  RESULTS
  A dual-chamber ICD (Medtronic 7250 Jewel AF) was implanted in 293 of 303 patients at 49 centers in Europe, Canada, and North America. Specific data were collected at implant and during a mean follow-up period of 7.9+/-4.7 months. There were no clinically evident failures to detect and treat ventricular arrhythmias. In patients with at least one of the dual-chamber detection criteria activated, 1,056 of 1,192 episodes of ventricular tachycardia or fibrillation detected were judged to be appropriate (89% positive predictive accuracy). Therapy efficacy was 100% in the ventricular fibrillation zone and 98% in the ventricular tachycardia zone. Positive predictive accuracy for detection of atrial episodes was 95% (1,052/1,107). For episodes classified as atrial tachycardia by the device, the efficacy of atrial antitachycardia pacing and high-frequency (50-Hz) burst pacing was 55% and 17%, respectively. High-frequency burst pacing terminated 16.8% of episodes classified as atrial fibrillation, and atrial defibrillation had an estimated efficacy of 76%. The actuarial estimates of 6-month complication-free survival and total survival were 88% and 94%, respectively.
  
  
  CONCLUSIONS
  This novel dual-chamber ICD is capable of safely and effectively discriminating atrial from ventricular tachyarrhythmias and of treating atrial tachyarrhythmias without compromising detection and treatment of ventricular tachyarrhythmias.
authors.affiliation: Department of Cardiology, University of Heidelberg, Germany. wolfgang_schoels@med.uni-heidelberg.de
authors.forename: W
authors.initials: W
authors.lastname: Schoels
authors.forename: C D
authors.initials: CD
authors.lastname: Swerdlow
authors.forename: W
authors.initials: W
authors.lastname: Jung
authors.forename: K M
authors.initials: KM
authors.lastname: Stein
authors.forename: K
authors.initials: K
authors.lastname: Seidl
authors.forename: C J
authors.initials: CJ
authors.lastname: Haffajee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000628:therapy; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D002170:Canada / Q000453:epidemiology; D006348:Cardiac Surgical Procedures / Q000295:instrumentation; D017147:Defibrillators, Implantable; D004869:Equipment Safety; D005060:Europe / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009656:North America / Q000453:epidemiology; D011237:Predictive Value of Tests; D016019:Survival Analysis; D013612:Tachycardia, Ectopic Atrial / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D013997:Time Factors; D016896:Treatment Outcome