Prognostic value of left ventricular contractile reserve and heart rate reserve in dilated cardiomyopathy

Abstract

Abstract Background Stress echocardiography (SE) allows to assess simultaneously left ventricular contractile reserve (LVCR) and heart rate reserve (HRR) in dilated cardiomyopathy (DCM). Aim To assess the prognostic value of LVCR and HRR in DCM patients Methods We prospectively enrolled 395 DCM patients with ejection fraction ≤40% (age 62±27 years, 270 males, 68%; ejection fraction 35±9%) referred from 9 certified laboratories, 264 with nonischemic DCM (67%) and 131 (33%) with ischemic DCM. All patients underwent clinically indicated SE. The employed stress modality was exercise (n=63), or pharmacological stress (n=332, with vasodilator, n=232; or dobutamine, n=100). LVCR was present with a rest-stress decrease ≥0.20 in wall motion score index. HRR was normal with a peak-rest value ≥1.80 with exercise or dobutamine and ≥1.22 with dipyridamole or adenosine stress. Results New regional wall motion abnormality was present in 46 (12%), LVCR in 131 (33%) and abnormal HRR in 275 (70%) DCM patients. During a median follow-up of 950 days (interquartile range: 360–1187 days) 71 deaths occurred. Annual mortality was 10.5%/year in DCM patients with abnormal HRR (HRR−) and absence of LVCR (LVCR−), 5.4%/year in patients with either abnormal HRR or absent LVCR, and 2.5%/year in patients with normal HRR and presence of LVCR (Figure 1). At multivariable analysis, only abnormal HRR (HR: 2.952, 95% CI: 1.547–5.630, p=0.001) but not absence of LVCR (HR: 1.545, 95% CI: 0.929–2.568, p=0.094), was independent predictors of survival. Conclusion Abnormal HRR predicts adverse prognosis in DCM patients, in addition to the presence of LV CR. Funding Acknowledgement Type of funding sources: None.