REPEATABILITY OF MEASUREMENTS OF PULMONARY VENOUS FLOW INDEXES

We investigated the measurement repeatability of four pulmonary venous flow indices. The indices were measured on 45 anonymised, transthorac ic Doppler recordings of adequate technical quality. Measurements were taken by two independent observers, and repeated after 10 days. Plus/ minus the repeatability coefficient, which was used to quantify repeat ability, gives the 95% probability limits for random variation between repeated measurements. The index D-diff, which is the difference in d uration of the pulmonary venous flow reversal during atrial systole an d the transmitral A-wave, had repeatability coefficients of 50 and 57 ms intra- and inter- observer. For the fraction of antegrade pulmonary venous now during ventricular systole, the coefficients were 12 and 1 3 percentage points, but improved to 6 and 7 among the high-quality re cordings. The retrograde pulmonary venous flow during atrial systole a s a fraction of the antegrade flow, had coefficients of 5 percentage p oints both intra- and inter-observer. The coefficient for the peak vel ocity of retrograde pulmonary venous flow was 0.05 m/s intra- and inte r-observer. Thus, the systolic fraction was the only index that showed a satisfactory repeatability. We suggest that if the other indices ar e used, measurements should be taken by a blinded observer to avoid ob server bias.