title: Automatic intraaortic balloon pump timing using an intrabeat dicrotic notch prediction algorithm.
abstract: OBJECTIVE
  The efficacy of intraaortic balloon counterpulsation (IABP) during arrhythmic episodes is questionable. A novel algorithm for intrabeat prediction of the dicrotic notch was used for real time IABP inflation timing control.
  
  
  METHODS
  A windkessel model algorithm was used to calculate real-time aortic flow from aortic pressure. The dicrotic notch was predicted using a percentage of calculated peak flow. Automatic inflation timing was set at intrabeat predicted dicrotic notch and was combined with automatic IAB deflation.
  
  
  RESULTS
  Prophylactic IABP was applied in 27 patients with low ejection fraction (< 35%) undergoing cardiac surgery. Analysis of IABP at a 1:4 ratio revealed that IAB inflation occurred at a mean of 0.6 +/- 5 ms from the dicrotic notch. In all patients accurate automatic timing at a 1:1 assist ratio was performed. Seventeen patients had episodes of severe arrhythmia, the novel IABP inflation algorithm accurately assisted 318 of 320 arrhythmic beats at a 1:1 ratio.
  
  
  CONCLUSIONS
  The novel real-time intrabeat IABP inflation timing algorithm performed accurately in all patients during both regular rhythms and severe arrhythmia, allowing fully automatic intrabeat IABP timing.
authors.affiliation: Department of Cardiac Surgery, San Raffaele University Hospital, Milan, Italy. schreuder@libero.it
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Schreuder
authors.forename: Alessandro
authors.initials: A
authors.lastname: Castiglioni
authors.forename: Andrea
authors.initials: A
authors.lastname: Donelli
authors.forename: Francesco
authors.initials: F
authors.lastname: Maisano
authors.forename: Jos R C
authors.initials: JR
authors.lastname: Jansen
authors.forename: Ramzi
authors.initials: R
authors.lastname: Hanania
authors.forename: Pat
authors.initials: P
authors.lastname: Hanlon
authors.forename: Jan
authors.initials: J
authors.lastname: Bovelander
authors.forename: Ottavio
authors.initials: O
authors.lastname: Alfieri
mesh_terms: D000368:Aged; D000465:Algorithms; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000503:physiopathology*; D001794:Blood Pressure; D006348:Cardiac Surgical Procedures; D006801:Humans; D007423:Intra-Aortic Balloon Pumping / Q000379:methods*; D008875:Middle Aged; D013997:Time Factors