title: Usefulness of negative dP/dt upstroke pattern for assessment of left ventricular relaxation in coronary artery disease.
abstract: It has been reported that regional asynchrony due to acute ischemia disturbs the exponential nature of left ventricular (LV) pressure reduction and may alter the pattern of (-)dP/dt upstroke curve. If LV pressure decreases exponentially during the isovolumic relaxation period (P = Ae-t/T + B, where A and B = constants, t = time and T = time constant), the (-)dP/dt upstroke curve should also be exponential and upward-convex because dP/dt = A(-t/T)e-t/T. To test this theory in humans, the LV (-)dP/dt upstroke curve was analyzed in 9 normal subjects, 12 patients with effort angina pectoris (AP) and 15 with old myocardial infarction (MI) under the basal conditions. The (-)dP/dt upstroke was convex-upward in all normal subjects, but convex-downward in 9 of 12 patients with AP and in all patients with MI, which suggests nonexponential decrease in LV pressure in the groups with AP and MI. The dP/dt (20/60), which is the ratio of the (-)dP/dt value at 20 ms after peak (-)dP/dt to that at 60 ms after peak (-)dP/dt, was significantly lower in the group with AP (1.70 +/- 0.07) and in the group with MI (1.61 +/- 0.13) than in normal subjects (2.08 +/- 0.18) (p less than 0.005). This indicates that (-)dP/dt upstroke 20 to 60 ms after peak (-)dP/dt increases more slowly in the groups with AP and MI than in normal subjects. Theoretical consideration showed that such a slower increase of the upstroke resulted from impaired early to midrelaxation.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Internal Medicine, Faculty of Medicine, Kyoto University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kumada
authors.forename: K
authors.initials: K
authors.lastname: Katayama
authors.forename: M
authors.initials: M
authors.lastname: Matsuzaki
authors.forename: R
authors.initials: R
authors.lastname: Kusukawa
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: C
authors.initials: C
authors.lastname: Kawai
mesh_terms: D000328:Adult; D003327:Coronary Disease / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D009200:Myocardial Contraction; D011312:Pressure