Prevalence of myocardial viability as detected by positron emission tomography in patients with ischemic cardiomyopathy

Background-Detection of myocardial viability is important in patients with ischemic cardiomyopathy. Restoration of blood flow to viable myocardium is associated with improved left ventricular function and improved patient pro gnosis. However, the prevalence of viable myocardium in patients with ische mic cardiomyopathy is unknown. Methods and Results-To determine the prevalence of myocardial viability, cl inical [N-13]ammonia/F-18-deoxyglucose PET studies performed in 283 patient s (age, 63 +/- 10 years) with ischemic heart disease (mean ejection fractio n, 26 +/- 8%) were visually analyzed for the presence and extent of viable and nonviable myocardium. The myocardium was divided into 19 segments. The extent of viable myocardium was considered "functionally" significant if gr eater than or equal to 5 segments (approximate to 25% of the left ventricul ar myocardium) exhibited a blood flow/metabolism mismatch and "prognostical ly" significant if 1 to 4 left ventricular segments did so. Of all patients , 41% had no evidence of viable myocardium, 55% had viable myocardium, and 4% had normal blood flow and metabolism within an enlarged left ventricle. Functionally significant viability was found in 27% and prognostically sign ificant viability in 28% of the patients. Multivariate analysis revealed th e presence of angina to be the only clinical parameter associated with the presence of functionally significant viability. Conclusions-Revascularization might improve patient prognosis in 55% and re sult in improved left ventricular function in 27% of all patients with isch emic cardiomyopathy.