title: Comparison of a novel, single-lead atrial sensing system with a dual-chamber implantable cardioverter-defibrillator system in patients without antibradycardia pacing indications: results of a randomized study.
abstract: BACKGROUND
  Supraventricular tachyarrhythmias are the main cause for inappropriate therapy by implantable cardioverter-defibrillators (ICDs). For better rhythm discrimination, an atrial electrogram is helpful and usually obtained from an additional atrial lead, even in the absence of sinus node or atrioventricular nodal disease. An A+-ICD system with integrated atrial sensing rings mounted 15 to 18 cm from the tip of an ICD lead may obviate the need to implant a separate atrial lead. The aim of the study was to compare the novel A+-ICD and a conventional dual-chamber (DR)-ICD.
  
  
  RESULTS
  Two hundred forty-nine patients with standard ICD indications but no requirement for antibradycardia pacing were randomized to receive an A+-ICD (n=124) or a DR-ICD (n=125). Implantation details, need for ICD system revision, long-term sensing, documented arrhythmia episodes, and the respective rhythm discrimination during follow-up were analyzed. The implantation time was significantly shorter in the A+-ICD group (67±30 vs 79±30 minutes, P=0.003). Mean P-wave amplitudes were 3.5±0.8 mV (A+-ICD) and 3.2±0.6 mV (DR-ICD) and remained stable during the follow-up period of 12 months. Surgical revision was necessary in 13 patients in the DR-ICD and 10 in the A+-ICD group. All 593 ventricular tachyarrhythmia episodes were correctly discriminated. Sensitivity and specificity of supraventricular tachyarrhythmia discrimination were not different between the study groups.
  
  
  CONCLUSIONS
  The novel A+-ICD system can be implanted faster and is equivalent to a standard DR-ICD with regard to the detection of ventricular tachyarrhythmias and supraventricular tachyarrhythmias. It represents a useful alternative to obtain atrial sensing.
authors.affiliation: University Hospital Basel, Basel, Switzerland. csticherling@uhbs.ch
authors.forename: Christian
authors.initials: C
authors.lastname: Sticherling
authors.forename: Markus
authors.initials: M
authors.lastname: Zabel
authors.forename: Sebastian
authors.initials: S
authors.lastname: Spencker
authors.forename: Udo
authors.initials: U
authors.lastname: Meyerfeldt
authors.forename: Lars
authors.initials: L
authors.lastname: Eckardt
authors.forename: Steffen
authors.initials: S
authors.lastname: Behrens
authors.forename: Michael
authors.initials: M
authors.lastname: Niehaus
mesh_terms: D000368:Aged; D000465:Algorithms; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology; D001282:Atrial Flutter / Q000175:diagnosis / Q000503:physiopathology; D001919:Bradycardia / Q000503:physiopathology*; D017147:Defibrillators, Implantable; D003937:Diagnosis, Differential; D004562:Electrocardiography; D004566:Electrodes; D022062:Electrophysiologic Techniques, Cardiac / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*