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 contractility pattern of the preconditioned myocardium remain unknown. The goal of this study was to investigate the evolution of postsystolic wall thickening 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 24h 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/dtmax 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 non ischemic 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 postsystolic wall thickening is almost abolished. These phenotype adaptations represent potential approaches for characterizing stunning and late preconditioning with repetitive ischemia in humans.