title: Noninvasive calibration of cardiac pressure transducers in patients with heart failure: an aid to implantable hemodynamic monitoring and therapeutic guidance.
abstract: BACKGROUND
  Implantable cardiac pressure monitors require assurance of calibration. This study evaluated if airway pressure responses during Valsalva maneuver (VM) can be used for calibrating intracardiac pressure transducers.
  
  
  RESULTS
  Thirty-eight heart failure patients performed VMs while cardiac and airway pressures were recorded. Patients were designated as Lower (L) if baseline PCW was <20 mm Hg (n = 17); otherwise, they were categorized as Higher (H) (n = 21). VMs were repeated in 9 H patients after nitroglycerin. Procedural success was 92% and there were no complications. Differences between filling pressure and airway pressure (effective pressure) were eliminated during VM (RA(eff) = -0.9 +/- 1.3, RVED(eff) = 1.2 +/- 1.1, PCW(eff) = 2.1 +/- 2.8, and LVED(eff) = 0.9 +/- 1.6 mm Hg), and filling pressures were highly correlated with airway pressure r = 0.94. On average, group H had higher PCW(eff) and LVED(eff) than L patients by 1.8 and 2.5 mm Hg (P < or = .002), respectively, but after nitrates their responses were identical.
  
  
  CONCLUSIONS
  The relationships between cardiac filling pressure and airway pressure during the Valsalva maneuver are sufficiently reliable to be considered as a new, noninvasive method for establishing the calibration of cardiac pressure sensors in patients with heart failure.
authors.affiliation: Division of Cardiology, Department of Medicine, and the Research Institute at Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Dougal
authors.initials: D
authors.lastname: McClean
authors.forename: Joseph
authors.initials: J
authors.lastname: Aragon
authors.forename: Aamer
authors.initials: A
authors.lastname: Jamali
authors.forename: Saibal
authors.initials: S
authors.lastname: Kar
authors.forename: Jay
authors.initials: J
authors.lastname: Ritzema-Carter
authors.forename: Richard
authors.initials: R
authors.lastname: Troughton
authors.forename: Henry
authors.initials: H
authors.lastname: Krum
authors.forename: Robert
authors.initials: R
authors.lastname: Doughty
authors.forename: William T
authors.initials: WT
authors.lastname: Abraham
authors.forename: James S
authors.initials: JS
authors.lastname: Whiting
authors.forename: Neal
authors.initials: N
authors.lastname: Eigler
mesh_terms: D000368:Aged; D001794:Blood Pressure; D002138:Calibration; D003326:Coronary Circulation; D003971:Diastole; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods; D011312:Pressure; D019736:Prostheses and Implants; D011669:Pulmonary Wedge Pressure; D012137:Respiratory System / Q000503:physiopathology; D013318:Stroke Volume; D014160:Transducers, Pressure; D014636:Valsalva Maneuver; D016277:Ventricular Function, Left