Volume loading–related changes in tissue Doppler images derived from the tricuspid valve annulus in dogs

OBJECTIVE: To investigate the relationship between preload and tricuspid valve annulus-derived tissue Doppler imaging (TDI) as an index of right ventricular (RV) filling in dogs. ANIMALS: 7 Beagles. PROCEDURES: Peak systolic RV pressure and RV end-diastolic pressure (RVEDP) were measured in anesthetized dogs. Pulsed Doppler was used to measure tricuspid valve inflow and pulmonary valve outflow velocities. The TDI velocities were measured at the lateral corner of the tricuspid valve annulus. Lactated Ringer's solution was infused at 200 mL/kg/h for 60 minutes via the cephalic vein. RESULTS: IV infusion significantly increased heart rate, RV pressure, and RVEDP. Early diastolic flow (E-wave) and ejection time significantly increased. The myocardial performance index (MPI) significantly decreased. Intravenous infusion significantly increased the ratio of the E'-wave (peak myocardial velocity during early diastole) to the A'-wave (peak myocardial velocity during late diastole; E':A' ratio) and myocardial velocity during systole (S'), early diastole (E'), and late diastole (A'). The TDI-isovolumic relaxation time and TDI-MPI decreased significantly. The RVEDP was correlated with late diastolic flow (A-wave), ratio of the E-wave to the A-wave (E:A ratio), E'-wave, A'-wave, S'-wave (peak myocardial velocity during systole), TDI-isovolumic relaxation time, TDI-MPI, and ratio of the E-wave to the E'-wave (E: E' ratio). The A-wave and E:A ratio and TDI-derived isovolumic relaxation time, S' duration, and E'-wave could predict the RVEDP. CONCLUSIONS AND CLINICAL RELEVANCE: The TDI velocities were affected by RV filling pressure in healthy dogs, whereas other TDI profiles, such as MPI and E':A' ratio, were independent of acute filling abnormalities.