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

Recovery of function is possible in patients with ischemic cardiomyopathy when left ventricular dysfunction is caused by stunning or hibernation. It is plausible that recovery of function after revascularization may take a longer time in hibernating myocardium compared with stunned myocardium. Accordingly, the time courses of functional recovery in hibernating and stunned myocardium were compared.

Patients (n=26) with ischemic cardiomyopathy undergoing surgical revascularization were studied; regional perfusion (resting (201)Tl single-photon emission CT), glucose utilization ((18)F-2-deoxyglucose single-photon emission CT), and contractile function (2D echocardiography) were assessed before revascularization. Dysfunctional segments with normal perfusion/glucose utilization were considered to be stunned, and dysfunctional segments with reduced perfusion/preserved glucose utilization were considered to be hibernating. Contractile function was reevaluated 3 months (early) and 14 months (late) after revascularization. Of the 266 dysfunctional segments, 57 (22%) were stunned, 62 (23%) were hibernating, and 147 (55%) were scar tissue. In stunned myocardium, contractile function improved significantly at 3 months, without further improvement at 14 months; 61% of the stunned segments improved at 3 months, and 9% improved at 14 months. In hibernating myocardium, contractile function improved at 3 months, with a further improvement at 14 months; 31% of the hibernating segments improved at 3 months, and 61% showed (additional) recovery at 14 months.

Stunned myocardium is likely to demonstrate early recovery of function, whereas hibernating myocardium may take a longer time to (fully) recover in function after revascularization.