not-yet-known not-yet-known not-yet-known unknown Background and aims: The assessment of left ventricular (LV) outflow velocity time integral (LVOT-VTI) has gained favor in the stratification of patients with heart failure (HF). We evaluated the prognostic significance of LVOT-VTI compared with the commonly used indices of LV outflow: cardiac index (CI) and stroke volume index (SVI), their reproducibility and cut-off values. Methods and results: 424 outpatients diagnosed with HF and LV systolic dysfunction (LV ejection fraction <50%) underwent a Doppler echocardiographic examination, including the assessment of CI, SVI and LVOT-VTI. The Bland-Altman analysis showed LVOT-VTI the most reproducible outflow index. The study follow-up duration was 3.5 years (interquartile range 1.6 to 6.5), at the end of which there were 94 cardiovascular deaths (29%). Cox regression univariate analysis showed that LVOT-VTI was the most predictive of the study end-point. The ratio of tricuspid annular displacement-to-pulmonary artery systolic pressure (TAPSE/PASP) (p<0.0001), LVOT-VTI (p=0.0001) and end-systolic volume index (p=0.0006) independently predicted the study end-point. At Receiver-operating characteristic (ROC) analysis, LVOT-VTI <12.0 cm had the best sensitivity and specificity for predicting cardiovascular mortality. Reduced LV EF (p=0.0011), raised BNP levels (p=0.0053) and high LV filling pressure (p=0.044) were associated with low LVOT-VTI in multivariate logistic regression analysis. Patients with low LVOT-VTI and TAPSE/PASP<0.32 mm/mmHg exhibited the worst prognosis on Kaplan-Meier survival curves (p<0.0001). Conclusions. A LVOT-VTI < 12.0 cm represents the best predictor of the cardiovascular outcome and proved the most reproducible index of LV forward flow in patients with chronic HF and systolic dysfunction.

Purpose: This study was a quality-control study of resting and exercise echocardiography (EDE) variables measured by 19 echocardiography laboratories with proven experience participating in the RIGHT Heart International NETwork. Methods: All participating investigators reported the requested variables from ten randomly selected exercise stress tests. Intraclass correlation coefficients (ICC) were calculated to evaluate the inter-observer agreement with the core laboratory. Inter-observer variability of resting and peak exercise tricuspid regurgitation velocity (TRV), right ventricular outflow tract acceleration time (RVOT Act), tricuspid annular plane systolic excursion (TAPSE), tissue Doppler tricuspid lateral annular systolic velocity (S’), right ventricular fractional area change (RV FAC), left ventricular outflow tract velocity time integral (LVOT VTI), mitral inflow pulsed wave Doppler velocity (E), diastolic mitral annular velocity by TDI (e’) and left ventricular ejection fraction (LVEF) was measured. Results: The accuracy of 19 investigators for all variables ranged from 99.7% to 100%. ICC was > 0.80 for all observers. Inter-observer variability for resting and exercise variables was for TRV = 3.8 to 2.4%, E = 5.7 to 8.3%, e’ = 6 to 6.5%, RVOT Act = 9.7 to 12, LVOT VTI = 7.4 to 9.6%, S’= 2.9 to 2.9% and TAPSE = 5.3 to 8%. Moderate inter-observer variability was found for resting and peak exercise RV FAC (15 to 16%). LVEF revealed lower resting and peak exercise variability of 7.6 and 9%. Conclusions: When performed in expert centers EDE is a reproducible tool for the assessment of the right heart and the pulmonary circulation