Hemodynamic determinants of pulmonary valve motion during systole in experimental pulmonary hypertension.

Abstract

To clarify the determinants of pulmonary valve (PV) motion in pulmonary hypertension, we examined the correlations among PV echo patterns, the pulmonary artery (PA) flow curve just above the PA orifice and the pulmonary artery-right ventricle (PA-RV) pressure gradient. By constricting the PA, we could produce a variety of PV echo patterns, including midsystolic semiclosure in open-chest dogs. Throughout the experiments, the PV echo pattern and PA flow curve were similar in pattern and timing. When the PV echo showed midsystolic semiclosure with reopening. The PA flow curve showed a transient decrease followed by a transient increase during midsystole. The PA-RV pressure gradient became transiently positive (PA pressure greater than RV pressure) and then negative in midsystole only when the PV echo showed midsystolic semiclosure with reopening. In conclusion, PV motion during systole may be instantaneously determined by PA flow change and the PA-RV pressure gradient during the cardiac cycle in experimental pulmonary hypertension.

Magnetic Resonance–Derived 3-Dimensional Blood Flow Patterns in the Main Pulmonary Artery as a Marker of Pulmonary Hypertension and a Measure of Elevated Mean Pulmonary Arterial Pressure

“…During the midsystolic period, when the pressure gradient between the right ventricle and pulmonary artery is already close to zero, a short positive wave occurs in the time course of the pressure gradient for patients with manifest PH. 25,26 We conjecture that this wave, supported by the present high velocities, triggers vortex formation in the main pulmonary artery.…”

“…25,26 This fact explains the reduced acceleration time in patients with manifest PH, which is the rationale for attempts to assess mPAP and PH directly by noninvasive methods. 2,3,[7][8][9][10][11] We also observed reduced acceleration times in patients with manifest PH.…”

Characteristics of patent foramen ovale associated with cryptogenic stroke. A biplane transesophageal echocardiographic study.

“…Echocardiographic evidence for elevated right ventricular systolic pressure such as pulmonic valve notching 13 and flat interventricular septum 14 was sought. When feasible, tricuspid regurgitation velocity was measured using continuous-wave Doppler to assess for right ventricular systolic pressure.…”

<b>Echocardiographic Evaluation of Right Cardiac Function in Patients with Chronic Pulmonary Diseases</b>

“…The following issues have been evaluated morphologically by several investigators: changes in the RV diameter, 1,2) RV contractility, 3,4) the severity of RV hypertrophy caused by pressure overload, 5) fluttening of the ventricular septum, 6) early diastolic dip depicted by the M-mode method during movement of the ventricular septum, 7) and mid systolic closure of the pulmonary arterial valve and disappearance of a dip depicted by the M-mode method. 8,9) In addition, right atrial pressure has been evaluated based on the diameter of the inferior vena cava. 10) In a clinical setting, however, echocardiographic evaluation of the right heart system is more difficult than that of the left heart system because the thinner RV wall makes echocardiographic visualization of the right heart system more difficult compared to visualization of the left heart system.…”

“…However, echocardiography is currently one of the most useful procedures for such evaluation because it allows the simple, noninvasive, and reproducible measurement of cardiac function at the bedside. In recent years, the function of the right heart system has been evaluated echocardiographically through changes in RV morphology, [1][2][3][4][5][6][7][8][9][10] and the use of the Doppler method. [11][12][13][14][15][16][17][18][19] The findings were then compared with the results obtained by invasive procedures, and a satisfactory correlation was obtained between the two data sets.…”