Prognostic value of left-ventricular and peripheral vascular performance in patients with dilated cardiomyopathy

BACKGROUND: The goal of the heart during exercise is to increase cardiac output to metabolizing tissues. Our aim was to assess the relative role of systolic versus diastolic dysfunction in modulating cardiac output in patients with idiopathic left-ventricular (LV) dysfunction. METHODS: We enrolled 51 patients (LV ejection fraction, mean +/- SD, = 36% +/- 9%) and 24 controls with a normal LV ejection fraction. All were scheduled for exercise radionuclide angiography for the evaluation of LV functional reserve, and were followed for a median of 129 months. RESULTS: Stroke volume increased in control subjects mainly through a decrease in end-systolic volume, while it increased in patients through an increase in end-diastolic volume (EDV), albeit heterogeneously. Patients were divided into group I, with stroke volume increase, versus group II, without stroke volume increase, during stress. Despite similar blunted inotropic reserves, group I showed a decrease in arterial elastance during stress: a better ventricular-arterial coupling occurred, leading to increased cardiac efficiency. At long-term follow-up, the overall event-free survival was 88% in group I, compared with 61% for group II (log rank = 4.7, P = .03). CONCLUSIONS: In the presence of idiopathic LV dysfunction, a preserved LV pumping reserve can be identified easily through stress-induced variations in the EDV and stroke volume, with a powerful, long-term death-risk stratification.