Right atrial appendage (RAA) blood flow pattern was analyzed in 42 normal subjects without cardiovascular disease (aged 30 to 48 years, mean 40 +/- 6) who underwent transesophageal echocardiography. RAA flow pattern was demonstrated to be bi-, tri- or quadriphasic and heart rate dependent (p < 0.01) in this study. In 15 subjects (36%), a biphasic pattern was observed. A triphasic pattern was observed in 12 subjects (28%). Fifteen subjects (36%) had a quadriphasic pattern. In these subjects, we observed a pattern consisting of two diastolic forward flow waves, each followed by a backward flow wave. Mean heart rates among subjects with bi-, tri- and quadriphasic patterns were 110 +/- 6, 91 +/- 4 and 72 +/- 13 beats/min, respectively. In the triphasic pattern, the onset of superior vena cava diastolic forward flow began 18 +/- 4 ms after the onset of tricuspid E wave, whereas the first diastolic forward flow wave in the RAA began 40 +/- 7 ms after onset of the tricuspid E wave. A similar relation was also noted in the quadriphasic pattern. This sequence was constant and independent of heart rate (p < 0.05), suggesting a temporal relation between right ventricular relaxation and the first diastolic forward flow wave in the RAA.