title: Reduction in postsystolic wall thickening during late preconditioning.
abstract: Brief coronary artery occlusion (CAO) and reperfusion induce myocardial stunning and late preconditioning. Postsystolic wall thickening (PSWT) also develops with CAO and reperfusion. However, the time course of PSWT during stunning and the regional function pattern of the preconditioned myocardium remain unknown. The goal of this study was to investigate the evolution of PSWT during myocardial stunning and its modifications during late preconditioning. Dogs were chronically instrumented to measure (sonomicrometry) systolic wall thickening (SWT), PSWT, total wall thickening (TWT = SWT + PSWT), and maximal rate of thickening (dWT/dt(max)). Two 10-min CAO (circumflex artery) were performed 24 h apart (day 0 and day 1, n = 7). At day 0, CAO decreased SWT and increased PSWT. During the first hours of the subsequent stunning, evolution of PSWT was symmetrical to that of SWT. At day 1, baseline SWT was similar to day 0, but PSWT was reduced (-66%), while dWT/dt(max) and SWT/TWT ratio increased (+48 and +14%, respectively). After CAO at day 1, stunning was reduced, indicating late preconditioning. Simultaneously vs. day 0, PSWT was significantly reduced, and dWT/dt(max) as well as SWT/TWT ratio were increased, i.e., a greater part of TWT was devoted to ejection. Similar decrease in PSWT was observed with a nonischemic preconditioning stimulus (rapid ventricular pacing, n = 4). In conclusion, a major contractile adaptation occurs during late preconditioning, i.e., the rate of wall thickening is enhanced and PWST is almost abolished. These phenotype adaptations represent potential approaches for characterizing stunning and late preconditioning with repetitive ischemia in humans.
authors.affiliation: Laboratoire de Pharmacologie, INSERM U660, Faculté de Médecine de Créteil, 8, rue Général Sarrail, 94010 CRETEIL Cedex, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Monnet
authors.forename: Laurence
authors.initials: L
authors.lastname: Lucats
authors.forename: Patrice
authors.initials: P
authors.lastname: Colin
authors.forename: Geneviève
authors.initials: G
authors.lastname: Derumeaux
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Dubois-Rande
authors.forename: Luc
authors.initials: L
authors.lastname: Hittinger
authors.forename: Bijan
authors.initials: B
authors.lastname: Ghaleh
authors.forename: Alain
authors.initials: A
authors.lastname: Berdeaux
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D004285:Dogs; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D009200:Myocardial Contraction; D017682:Myocardial Stunning / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015427:Reperfusion Injury / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D013599:Systole; D016896:Treatment Outcome; D014463:Ultrasonography