title: Quantification of left ventricular diastolic pressure-volume relations during routine cardiac catheterization by two-dimensional digital echo quantification and left ventricular micromanometer.
abstract: BACKGROUND
  Currently there is no simple clinical method for quantifying the left ventricular (LV) diastolic pressure-volume relation. Echocardiographic-automated endocardial border detection, however, may be combined with LV micromanometer to construct LV pressure-volume loops. We investigated the feasibility of on-line display and sampling of LV pressure-volume loops by such an approach. For this purpose we used a new echocardiographic digital echo quantification (DEQ) method in combination with LV pressures on-line and in real-time.
  
  
  METHODS
  Eighteen patients were screened by conventional echocardiography and DEQ. Ten of the patients with high quality images were included in the study. Left ventricular pressures and volumes were recorded simultaneously and were displayed on-line as pressure-volume loops. Changes in LV volume were induced by intravenous saline. Left ventricular chamber compliance was estimated as change in volume divided by change in pressure from minimum diastolic pressure to end-diastolic pressure (average LV chamber compliance).
  
  
  RESULTS
  Left ventricular pressure-volume loops were displayed on-line during the examination. When compared with the Simpson's method, DEQ underestimated end-diastolic volume (EDV) by 35% and overestimated end-systolic volume (ESV) by 14%. Beat-to-beat variability for ESV and EDV were 7.4% +/- 0.8% and 7.2% +/- 0.7 %, respectively. Volume loading increased LV end-diastolic pressure (LVEDP) from 14.0 +/- 1.6 to 24.7 +/- 2.0 mm Hg (P <.05) and EDV from 79 +/- 10 to 85 +/- 11 mL (NS), and decreased LV chamber compliance from 4.0 +/- 0.7 to 2.0 +/- 0.3 mL/mm Hg (P <.05).
  
  
  CONCLUSIONS
  The current study demonstrates that LV pressure-volume loops can be displayed and evaluated in real-time during routine cardiac catheterization. This may represent a clinically useful method for identifying patients with reduced chamber compliance. The underestimation of the volumes by DEQ compared with the Simpson's method suggests that further refinements should be performed to improve the endocardial border detection algorithm.
authors.affiliation: Institute of Surgical Research, Rikshospitalet, Oslo, Norway.
authors.forename: Stig
authors.initials: S
authors.lastname: Urheim
authors.forename: Reidar
authors.initials: R
authors.lastname: Bjørnerheim
authors.forename: Knut
authors.initials: K
authors.lastname: Endresen
authors.forename: Karleif
authors.initials: K
authors.lastname: Vatne
authors.forename: Stein Inge
authors.initials: SI
authors.lastname: Rabben
authors.forename: Vidar
authors.initials: V
authors.lastname: Sørhus
authors.forename: Otto A
authors.initials: OA
authors.lastname: Smiseth
mesh_terms: D000368:Aged; D000465:Algorithms; D001810:Blood Volume; D006328:Cardiac Catheterization; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D003971:Diastole; D004452:Echocardiography / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D018709:Statistics, Nonparametric; D016277:Ventricular Function, Left / Q000502:physiology*; D017725:Ventricular Pressure