title: Loss of adrenergic augmentation of diastolic intra-LV pressure difference in patients with diastolic dysfunction: evaluation by color M-mode echocardiography.
abstract: OBJECTIVE
  The aim of this study was to evaluate the hypothesis that the adrenergic response of the intraventricular pressure difference (IVPD) is reduced in patients with preserved ejection fraction (EF) and diastolic dysfunction (DD).
  
  
  BACKGROUND
  In early diastole, there is a progressive IVPD extending from the left atrium (LA) to the left ventricular (LV) apex. In response to adrenergic stimulation, as occurs during exercise, the IVPD increases allowing rapid filling without an abnormal increase in LA pressure. Patients with heart failure with a reduced EF have impaired adrenergic augmentation of the IVPD.
  
  
  METHODS
  We studied 166 consecutive patients undergoing dobutamine stress echocardiography who had no inducible ischemia and an EF ≥50%, of which 21 had normal diastolic function, 14 had impaired relaxation (grade 1), 80 had pseudonormal filling (grade 2), and 51 had restrictive filling (grade 3). Color M-mode Doppler (CMMD) images of mitral inflow were obtained at rest and during low (10 μg/kg/min) and peak (20 to 40 μg/kg/min) doses of dobutamine. The total IVPD from the LA to LV apex, LA to mid-LV, and mid-LV to the LV apex were calculated using the CMMD data to integrate the Euler equation.
  
  
  RESULTS
  Total IVPD was not different between groups at rest. With dobutamine, the total IVPD increased by 2.20 ± 1.95 mm Hg in normal subjects and by only 0.73 ± 1.33 mm Hg, 1.84 ± 1.63 mm Hg, and 1.08 ± 1.57 mm Hg in patients with grades 1, 2, and 3 DD, respectively. This difference was due to a failure in augmentation of IVPD from the mid-LV to the LV apex, indicating reduced apical ventricular suction with DD, whereas the IVPD from the LA to the mid-LV responded similarly to dobutamine in normal subjects and those with DD.
  
  
  CONCLUSIONS
  In patients with preserved EF, DD is associated with a reduced adrenergic augmentation of the IVPD from the mid-LV to the LV apex, reflecting less apical suction.
authors.affiliation: Section on Cardiology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157-1045, USA.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ohara
authors.forename: Cassie L
authors.initials: CL
authors.lastname: Niebel
authors.forename: Kelley C
authors.initials: KC
authors.lastname: Stewart
authors.forename: John J
authors.initials: JJ
authors.lastname: Charonko
authors.forename: Min
authors.initials: M
authors.lastname: Pu
authors.forename: Pavlos P
authors.initials: PP
authors.lastname: Vlachos
authors.forename: William C
authors.initials: WC
authors.lastname: Little
mesh_terms: D000322:Adrenergic Agonists; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D003971:Diastole; D004280:Dobutamine; D018618:Echocardiography, Doppler, Color; D025401:Echocardiography, Stress; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016277:Ventricular Function, Left; D017725:Ventricular Pressure
chemical_list: D000322:Adrenergic Agonists; D004280:Dobutamine