Poster Session: Dobutamine Stress Echo

Purpose: Idiopathic pulmonary arterial hypertension (IPAH) prognosis depends on the capability of the right ventricle (RV) to preserve its function in face of increased afterload.We hypothesize that, as for the left ventricle, right intra-ventricular (IVD) dyssynchrony may have a negative effect on the overloaded RV.The aim of the study was to assess right IVD by incorporating activation times of longitudinal deformation across all RV segments, representing the longitudinal deformation the major contribution to chamber contraction.Methods: Eighty patients with IPAH (52 female subjects), without right bundle branch block, were consecutively enrolled.All patients underwent WHO functional evaluation, 6-minutes walking test, right heart catheterization and a comprehensive echocardiographic examination within 24 hours from invasive procedure.RV longitudinal myocardial deformation was assessed by using 2D Speckle Tracking Echocardiography (2DSTE).We defined RV dyssynchrony, next called RV-SD4, as the standard deviation (SD) of the time-intervals between QRS onset and peak longitudinal systolic strain of mid and basal segments of the RV free wall and the inter-ventricular septum.Results: Patients with IPAH showed regional abnormalities of RV function in terms of time to peak of longitudinal systolic strain as expressed by RV-SD4.Multivariate regression analysis revealed that QRS duration, RV end-diastolic area and pulmonary vascular resistances (PVR) were independent predictors of RV-SD4 (r2 =0,36; p=,0.00001).Actuarial rates of patients who experienced clinical worsening (CW) were 25% at 6 months, 32% and 48% at 1 and 2 years respectively.Event-free survivors had better WHO functional class, 6-minutes walking distance, hemodynamic status, morphological and functional echocardiographic parameters.Multivariate analysis showed cardiac index (unit 0.5, HR 0.36, CI 95% 0.23-0.57),RV fractional area change (unit 5, HR 0.79, CI 95% 0.67-0,93) and RV-SD4 (unit 5, HR 1.06 CI 95% 1.00-1.13)as independent predictors of CW (x 2 =46.8, p=000001).The optimal ROC-derived RV-SD4 cut-off value as indicator of CW was ≥ 23 (Sensibility 92%, Specificity 67%).Conclusions: Our findings suggest that right intra-ventricular dyssynchrony can be accurately described by the 2DSTE derived measure RV-SD4.That index of RV dyssynchrony can help to distinguish non invasively those IPAH patients with a worse clinical and hemodynamic profile and could be considered among independent predictors of clinical worsening.