Objective:
Non-invasive intraventricular pressure gradients (IVPG) based on color m mode is a load-independent diastolic function evaluation technique established in recent years. The mitral inflow pattern dominated by heart rate in hypertension is a strong predictor of prognosis. However, data on the effects of mitral inflow pattern on IVPG is lacking.
Design and method:
One hundred twenty-five rats were received infrarenal abdominal aortic coarctation surgery to produce pressure overload to induce hypertension. These rats were divided into three groups according to mitral inflow pattern, EA infusion (group 1), EA half infusion (group 2, inflow infused while the mitral annulus movement not infuse) and EA separate group (group 3). The conventional echocardiography and color m mode sampling were performed 3 and 6 weeks after operation under general anesthesia by 2.5% isoflurane with 1L/min oxygen. IVPG estimation was obtained based on the color m mode graph analyzing by Euler equation.
Results:
Total IVPG, the basal IVPG and resting heart rate in group 1 was significantly higher than group 2 and group 3 while the papillary to apical IVPG, mitral valve inflow peak velocity and E/E’ ratio among these three groups were no different. The changes in resting heart rate in group1 (r = 0.49, p = 0.015) were correlated with total IVPG and the changes in resting heart rate in group 1 (r = 0.52, p = 0.009) and group 2 (r = -0.10, p = 0.037) were correlated with papillary to apical IVPG. Among these 3 groups, these patients are divided into high IVPG and low IVPG two group, in high IVPG group (n = 58), 21, 16, 19 belong to group 1, 2, 3, respectively verses 34, 23, 10 belong to group 1, 2, 3 respectively in low IVPG group(n = 67).
Conclusions:
Accuracy and reliability of IVPG in severe surgical hypertension patients are higher than in mild hypertension and IVPG was not influenced by mitral inflow pattern. Mitral inflow velocity and IVPG changes are qualitatively similar increased and active relaxation also promoted, when resting heart rate increases.
