title: Multicenter, prospective, randomized safety and efficacy study of a new atrial-based managed ventricular pacing mode (MVP) in dual chamber ICDs.
abstract: BACKGROUND
  Ventricular desynchronization caused by right ventricular pacing may impair ventricular function and increase risk of heart failure (CHF), atrial fibrillation (AF), and death. Conventional DDD/R mode often results in high cumulative percentage ventricular pacing (Cum%VP). We hypothesized that a new managed ventricular pacing mode (MVP) would safely provide AAI/R pacing with ventricular monitoring and DDD/R during AV block (AVB) and reduce Cum%VP compared to DDD/R.
  
  
  METHODS
  MVP RAMware was downloaded in 181 patients with Marquis DR ICDs. Patients were initially randomized to either MVP or DDD/R for 1 month, then crossed over to the opposite mode for 1 month. ICD diagnostics were analyzed for cumulative percentage atrial pacing (Cum%AP), Cum%VP, and duration of DDD/R pacing for spontaneous AVB.
  
  
  RESULTS
  Baseline characteristics included age 66 +/- 12 years, EF 36 +/- 14%, and NYHA Class II-III 36%. Baseline PR interval was 190 +/- 53 msec and programmed AV intervals (DDD/R) were 216 +/- 50 (paced)/189 +/- 53 (sensed) msec. Mean Cum%VP was significantly lower in MVP versus DDD/R (4.1 +/- 16.3 vs 73.8 +/- 32.5, P < 0.0001). The median absolute and relative reductions in Cum%VP during MVP were 85.0 and 99.9, respectively. Mean Cum%AP was not different between MVP versus DDD/R (48.7 +/- 38.5 vs 47.3 +/- 38.4, P = 0.83). During MVP overall time spent in AAI/R was 89.6% (intrinsic conduction), DDD/R 6.7% (intermittent AVB), and DDI/R 3.7% (AF). No adverse events were attributed to MVP.
  
  
  CONCLUSIONS
  MVP safely achieves functional atrial pacing by limiting ventricular pacing to periods of intermittent AVB and AF in ICD patients, significantly reducing Cum%VP compared to DDD/R. MVP is a universal pacing mode that adapts to AVB and AF, providing both atrial pacing and ventricular pacing support when needed.
authors.affiliation: Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. mosweeney@partners.org
authors.forename: Michael O
authors.initials: MO
authors.lastname: Sweeney
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Ellenbogen
authors.forename: David
authors.initials: D
authors.lastname: Casavant
authors.forename: Robert
authors.initials: R
authors.lastname: Betzold
authors.forename: Todd
authors.initials: T
authors.lastname: Sheldon
authors.forename: Feng
authors.initials: F
authors.lastname: Tang
authors.forename: Megan
authors.initials: M
authors.lastname: Mueller
authors.forename: John
authors.initials: J
authors.lastname: Lingle
mesh_terms: D000328:Adult; D000368:Aged; D001283:Atrioventricular Node / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects; D017147:Defibrillators, Implantable; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies