title: Effect of pacemaker rate-adaptation on 24 h beat-to-beat heart rate and blood pressure profiles.
abstract: OBJECTIVE
  The aims of the study were to evaluate the 24-h beat-to-beat heart rate (RR) and blood pressure changes during closed loop stimulation (DDD-CLS) pacing and conventional fixed rate DDD pacing with respect to spontaneous activity.
  
  
  METHODS
  We simultaneously and continuously measured beat-to-beat heart rate and blood pressure for 24 h in patients implanted with Inos2+ (Biotronik GmbH, Berlin, Germany). A randomised cross-over comparison of DDD-CLS and DDD pacing was performed by short- and long-term analyses.
  
  
  RESULTS
  Seventeen patients (10 males, aged 46-85 years) were enroled in the study: 11 completed the protocol. The percentage of atrial stimulation was 72.87% during DDD-CLS and 38.36% in DDD (P=0.003). All patients were 100% stimulated in the ventricle. On average, the percentage increase of paced RR intervals with respect to spontaneous beats was only 7.4% in DDD-CLS but 20.1% in DDD (P=0.0001). A significant correlation between spontaneous and paced RR profiles was obtained only during DDD-CLS (r(DDD-CLS)=0.77, r(DDD)=0.23, P=0.01). Short-term analysis revealed a 3.79% reduction of the escape interval in DDD-CLS and 8.19% in DDD, and the relative fall in diastolic blood pressure was 1.14% in DDD-CLS and 3.81% in DDD.
  
  
  CONCLUSIONS
  DDD-CLS provided physiological heart rate fluctuations throughout the 24-h test. The blood pressure profiles of paced and spontaneous beats were comparable. The onset of paced rhythm in DDD-CLS resulted in a less pronounced decrease in heart rate and fall in diastolic pressure than in DDD.
authors.affiliation: Institute of the Heart and Great Vessels, University La Sapienza, Rome, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Quaglione
authors.forename: Giovanni
authors.initials: G
authors.lastname: Calcagnini
authors.forename: Federica
authors.initials: F
authors.lastname: Censi
authors.forename: Mario
authors.initials: M
authors.lastname: Malavasi
authors.forename: Marco
authors.initials: M
authors.lastname: Raveggi
authors.forename: Gianluca
authors.initials: G
authors.lastname: Biancalana
authors.forename: Pietro
authors.initials: P
authors.lastname: Bartolini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Critelli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial