Validation of isovolumic relaxation flow propagation velocity as an index of ventricular relaxation.

To test the applicability of isovolumic relaxation flow propagation velocity (IRFPV) as an indicator of relaxation, 38 patients undergoing cardiac catheterization for chest pain were included. The time constant of isovolumic left ventricular (LV) pressure decline (tau) had a significant correlation with the LV end-diastolic pressure, the peak negative dp/dt, the LV end-diastolic dimension, the fractional shortening, the late diastolic transmitral flow velocity, the early and late diastolic mitral annular velocities, the rapid filling flow propagation velocity, and the natural logarithms of heart rate, ejection fraction, LV end-systolic dimension and IRFPV (r = -0.773, p < 0.001). IRFPV was selected as the major independent determinant of tau, explaining 46% of its variance. In prediction of tau > or =42 ms, the sensitivity and specificity were 100% and 83% for IRFPV < or =104 cm/s, 77% and 67% for the rapid filling flow propagation velocity < or =50 cm/s, and 58% and 67% for the early diastolic mitral annular velocity < or =8 cm/s, respectively. In conclusion, our data suggest that IRFPV could be a better marker of LV relaxation than other parameters, as the rapid filling flow propagation velocity or the early diastolic mitral annular velocity.