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Aims Although the left ventricular (LV) dysfunction in pre-capillary pulmonary hypertension (PH) has been recently recognized, the mechanism of LV dysfunction in this entity is not completely understood. We thus aimed to elucidate the determinants of intraventricular pressure difference (IVPD), a measure of LV suction, in pre-capillary PH. Methods and results Right heart catheterization and echocardiography were performed in 86 consecutive patients with pre-capillary PH (57 ± 18 years, 85% female). IVPD was determined using colour M-mode Doppler to integrate the Euler equation. In overall, IVPD was reduced compared to previously reported value in normal subjects. In univariable analyses, QRS duration (P = 0.028), LV ejection fraction (P = 0.006), right ventricular (RV) end-diastolic area (P < 0.001), tricuspid annular plane systolic excursion (P = 0.004), and LV early-diastolic eccentricity index (P = 0.009) were associated with IVPD. In the multivariable analyses, RV end-diastolic area and LV eccentricity index independently determined the IVPD. Conclusion Aberrant ventricular interdependence caused by RV enlargement could impair the LV suction. This study first applied echocardiographic IVPD, a reliable marker of LV diastolic suction, to investigate the mechanism of LV diastolic dysfunction in pre-capillary PH.

Aims The detection of increased left ventricular (LV) chamber stiffness may play an important role in assessing cardiac patients with potential but not overt heart failure. A non-invasive method to estimate it is not established. We investigated whether the echocardiographic backward/forward flow volume ratio from the left atrium (LA) during atrial contraction reflects the LV chamber stiffness. Methods and results We studied 62 patients who underwent cardiac catheterization and measured their left ventricular end-diastolic pressure (LVEDP) and pressure increase during atrial contraction (Delta Pa) from the LV pressure waveform. Using the echocardiographic biplane method of disks, we measured the LV volume change during atrial contraction indexed to the body surface area (Delta Va), and Delta Pa/Delta Va was calculated as a standard for the LV operating chamber stiffness. Using pulsed Doppler echocardiography, we measured the time-velocity integral (TVI) of the backward pulmonary venous (PV) flow during atrial contraction (I-PVA) and the ratio of I-PVA to the PV flow TVI throughout a cardiac cycle (F-PVA). We also measured the TVI of the atrial systolic forward transmitral flow (I-A) and the ratio of the I-A to the transmitral TVI during a cardiac cycle (F-A) and calculated I-PVA/I-A and F-PVA/F-A. IPVA/IA and F-PVA/F-A were well correlated with Delta Pa/Delta Va (r = 0.79 and r = 0.81) and LVEDP (r = 0.73 and r = 0.77). The areas under the ROC curve to discriminate LVEDP > 18mmHg were 0.90 for I-PVA/I-A and 0.93 for F-PVA/F-A. Conclusion The F-PVA/F-A, the backward/forward flow volume ratio from the LA during atrial contraction, is useful for noninvasive assessments of LV chamber stiffness and elevated LVEDP.