The reference values for right ventricular (RV) filling of normal persons and the effects of physiologic variables in a large series have not been described. The objective of this study was to characterize superior vena cava, hepatic vein, and RV inflow Doppler measurements in a large normal reference group to reflect the aging process, gender, heart rate, and effects of respiration. We prospectively performed pulsed-wave Doppler echocardiography of the superior vena cava, hepatic vein, and RV inflow during inspiration, expiration, and apnea in 115 healthy volunteers (62 women and 53 men) ranging in age from 21 to 84 years (mean +/- SEM 48 +/- 17). For analysis, the study subjects were classified by age into 2 groups: those < 50 years of age (group 1; n = 60) and those > or = 50 years of age (group 2; n = 55). Multiregression models were used to assess the influence of age, gender, and heart rate on Doppler variables. There were important differences in superior vena cava and RV inflow between the 2 groups. Group 2 had a greater superior vena cava peak atrial flow velocity (16 +/- 3 vs 13 +/- 3 cm/s), flow integrals (1.5 +/- 0.4 vs 1.1 +/- 0.3 cm), and reverse flow as a percentage of forward flow (17 +/- 6% vs 14 +/- 6%) than group 1. In group 2, peak RV inflow early filling velocity (41 +/- 8 vs 51 +/- 7 cm/s) and ratio of early filling-to-atrial filling (1.3 +/- 0.4 vs 2 +/- 0.5) were lower than that of group 1. Likewise, peak atrial filling velocity was higher (33 +/- 8 vs 27 +/- 8 cm/s) and deceleration time was longer (198 +/- 23 vs 188 +/- 22 ms) in group 2. The superior vena cava and hepatic vein peak forward flow velocities were significantly higher during inspiration than during expiration and apnea. Similarly, RV inflow velocities were significantly higher during inspiration than in expiration and apnea. Multiregression analysis showed that age, gender, and heart rate had important effects on Doppler variables. Thus, this study demonstrates the effects of aging and normal physiologic variable flow velocities in the superior vena cava, hepatic veins, and RV inflow in a large series of normal subjects.