Time course of functional recovery of stunned and hibernating segments after surgical revascularization

Background-Recovery of function is possible in patients with ischemic cardi omyopathy when left ventricular dysfunction is caused by stunning or hibern ation. It is plausible that recovery of function after revascularization ma y take a longer time in hibernating myocardium compared with stunned myocar dium. Accordingly, the time courses of functional recovery in hibernating a nd stunned myocardium were compared. Methods and Results-Patients (n=26) with ischemic cardiomyopathy undergoing surgical revascularization were studied; regional perfusion (resting Tl-20 1 single-photon emission CT), glucose utilization (F-18-2-deoxyglucose sing le-photon emission CT), and contractile function (2D echocardiography) were assessed before revascularization. Dysfunctional segments with normal perf usion/glucose utilization were considered to be stunned, and dysfunctional segments with reduced perfusion/preserved glucose utilization were consider ed to be hibernating. Contractile function was reevaluated 3 months (early) and 14 months (late) after revascularization. Of the 266 dysfunctional seg ments, 57 (22%) were stunned. 62 (23%) were hibernating, and 147 (55%) were scar tissue. In stunned myocardium, contractile function improved signific antly at 3 months, without further improvement at 14 months; 61% of the stu nned segments improved at 3 months, and 9% improved at 14 months. In hibern ating myocardium, contractile function improved at 3 months, with a further improvement at 14 months: 31% of the hibernating segments improved at 3 mo nths, and 61% showed (additional) recovery at 14 months. Conclusions-Stunned myocardium is likely to demonstrate early recovery of f unction, whereas hibernating myocardium may take a longer time to (fully) r ecover in function after revascularization.