Reference ranges and determinants of right ventricle outflow tract acceleration time in healthy adults by two-dimensional echocardiography

The right ventricular outflow tract acceleration time (RVOT-AT) has shown to progressively shorten with increasing degrees of pulmonary pressure. However, the physiologic ranges of RVOT AT are based on small sample sizes and have not been investigated regarding their determining factors. The aim of this study was to investigate reference values and determining factors of RVOT-AT in a large population of healthy subjects and by values described in the literature. In the first part of the study, 1029 healthy subjects (mean age 45.6 ± 16.0 years, 565 (54.7 %) females) were prospectively assessed by clinical examination including demography, vital signs and echocardiography. In the second part, we performed a pooled analysis of eight published studies describing RVOT-AT in healthy subjects (n = 450). Statistical analysis included the calculation of 5 % quantiles for defining reference values. RVOT-AT significantly but weakly correlated with age (r: -0.207; p < 0.001), body mass Index (r: -0.16), systolic (r: -0.158) and diastolic (r: -0.137) blood pressure, heart rate (r: -0.197) and left ventricular (LV) E/A ratio (r: 0.229) (all p < 0.001). No differences were found with regards to sex. In a synopsis of both prospective and literature-based data sets, RVOT-AT weighted means was 138.51 ms and the 5 % quantile was 104.7 ms (95 % confidence interval 98.2-110.1). This study delineates the range of RVOT-AT in healthy adults and it's determining factors. Our study is in line with the cut-off value stated by the European guidelines with an RVOT-AT ≤105 ms denoting abnormal values.