The dependence of pressure half-time on initial and mean pressure gradients: Exercise Doppler in patients with St. Jude valves

T. Rosamond, Z. Vered, J. E. Perez

Research output: Contribution to journalArticlepeer-review

Abstract

To assess the hemodynamic factors that influence the Doppler-derived mitral pressure half-time, we studied 11 patients with St. Jude valves in place, with constant effective mitral orifice area. Mitral pressure half-time, heart rate, time velocity integral, peak and mean pressure gradients were measured at rest and immediately after exercise. Despite in vitro stable effective orifice area in St. Jude valves, the pressure half-time decreased with exercise (95.0 ± 6.6 ms (SE) to 62.3 ± 4.7 ms; p < 0.01) as heart rate increased (73.8 ± 2.2 to 99.2 ± 3.2 beats/min; p < 0.01). Peak (early diastolic) and mean pressure gradients increased (6.3 ± 0.7 to 9.8 ± 0.9 mmHg and 2.5 ± 0.2 to 3.9 ± 0.3 mmHg, respectively; p < 0.05 for both). Mean transmitral time velocity integral did not change (26.6 ± 1.0 and 27.1 ± 1.8 cm; p = NS). Thus, under conditions of fixed effective orifice area, the mitral pressure half-time varies inversely with the peak and mean pressure gradients. This study suggests that the initial pressure gradient and volume flow should be considered when interpreting changes in Doppler pressure half-time as indicative of changes in mitral valve area.

Original languageEnglish
Pages (from-to)227-234
Number of pages8
JournalJournal of Cardiovascular Technology
Volume9
Issue number3
StatePublished - 1990
Externally publishedYes

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