title: Can left ventricular diastolic stiffness be measured noninvasively?
abstract: BACKGROUND
  A noninvasive estimation of left ventricular (LV) diastolic chamber stiffness (K(LV)) is still a challenge. Experimental data suggests that K(lv) can be obtained by using Doppler mitral flow deceleration time (DT) as the only variable: K(lv) = (70/[DT-20])(2) mm Hg/mL. We assessed the accuracy of this noninvasive estimate of K(lv) by comparing it with invasive measurement of K(lv) in intact patients with a wide range of LV size and function under varying loading conditions.
  
  
  METHODS
  Twenty-five patients (age 54 +/- 12 years) with ischemic heart disease (n = 19) or primary LV dysfunction (n = 6), with a wide range of DT (79-324 ms) and ejection fraction (8%-57%), underwent simultaneous assessment of LV pressure by micromanometer and volume by 2-dimensional (2D) echocardiography-guided Doppler mitral flow velocity (where volume = mitral flow velocity integral x annular area) calibrated to 2D echocardiography stroke volume. Invasive K(lv) [delta pressure (from minimum to end-diastolic)/delta volume (during the same time interval)] was obtained at baseline and in 23 patients after LV unloading by prostaglandin E(1) (30-60 ng/kg/min) (n = 12), nitroglycerin (0.2 mg) (n = 9) or magnesium (1 g) (n = 2). Noninvasive K(lv) was estimated according to the above formula.
  
  
  RESULTS
  In this set of patients with normal mitral annular area (3.9 +/- 1.1 cm(2)/m(2)), multivariate analysis showed that DT is inversely related to K(lv) (P <.001) but not to left atrial chamber stiffness, LV volume, relaxation time constant, mitral valve opening pressure, or area. The relation between noninvasively calculated and directly measured K(lv) was close to the line of identity under all conditions, (y = 0.93x + 0.05, r = 0.67, n = 48, P <.001), although with a wide standard error of the estimate (0.26 mm Hg/mL).
  
  
  CONCLUSIONS
  We conclude that K(lv) can be calculated +/- 0.5 mm Hg/mL from noninvasively measured DT in patients.
authors.affiliation: Cardiology Service, Policlinico G.B. Rossi, Division of Cardiology, Ospedale Maggiore, University of Verona, P.le L.A. Scuro 10, 37134 Verona, Italy. paolo.marino@univr.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Marino
authors.forename: William C
authors.initials: WC
authors.lastname: Little
authors.forename: Andrea
authors.initials: A
authors.lastname: Rossi
authors.forename: Enrico
authors.initials: E
authors.lastname: Barbieri
authors.forename: Maurizio
authors.initials: M
authors.lastname: Anselmi
authors.forename: Gianni
authors.initials: G
authors.lastname: Destro
authors.forename: Antonia
authors.initials: A
authors.lastname: Prioli
authors.forename: Laura
authors.initials: L
authors.lastname: Lanzoni
authors.forename: Piero
authors.initials: P
authors.lastname: Zardini
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003971:Diastole / Q000502:physiology; D015150:Echocardiography, Doppler; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging*; D015999:Multivariate Analysis; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016277:Ventricular Function, Left / Q000502:physiology*