Time course of functional recovery after revascularization of hibernating myocardium: a contrast-enhanced cardiovascular magnetic resonance study

We sought to evaluate the relation between long-term functional outcome after revascularization in patients with chronic ischaemic left ventricular (LV) dysfunction and baseline extent of myocardial fibrosis. Thirty-five patients underwent cine and delayed contrast-enhanced cardiovascular magnetic resonance (deCMR) for the quantitative assessment of regional and global LV functions and segmental extent of hyperenhancement (SEH). Function was assessed 1 month before and 3, 6, and 24 +/- 12 months after revascularization, and temporal changes were related to baseline extent of hyperenhancement. The likelihood of functional improvement was inversely related to the SEH during the entire follow-up: at the end of the study period, segments with 1-25, 26-50, 51-75, and 76-100% SEH were 2, 5, 11, and 86 times, respectively, less likely to have functional improvement than segments without hyperenhancement (multilevel analysis, P < 0.001). Although improvement continued over the whole study period in all SEH groups, the time course was significantly more delayed in segments with more extensive hyperenhancement at baseline (multilevel analysis, P < 0.001). In patients with chronic ischaemic LV dysfunction, improvement of dysfunctional but viable myocardium can be considerably delayed. Both the likelihood and the time course of long-term functional improvement are related to the baseline amount of scar, as visualized by deCMR.