Usefulness of the ratio of transmitral E wave velocity to isovolumic relaxation flow propagation velocity for predicting left ventricular end-diastolic pressure

Intraventricular Isovolumic Relaxation Flow Patterns Studied by Using Vector Flow Mapping

AIMS

The purpose of this study was to characterize isovolumic relaxation flow (IRF) in the left ventricle (LV) in patients with a wide spectrum of LV dysfunction.

METHODS

Color Doppler flow imaging was performed in 61 patients with coronary artery disease, 29 patients with dilated cardiomyopathy, and 41 healthy controls. Vector flow mapping was used to analyze the Doppler data.

RESULTS

IRF patterns were divided into three types: pattern A, an apically directed flow; pattern B, a bidirectional flow with small scattered vortices; and pattern C, a large vortex persisting throughout the entire isovolumic relaxation (IVR) period. All controls demonstrated an IRF corresponding to pattern A. Of the 90 patients, 42 demonstrated IRF as pattern A, 26 as pattern B, and 22 as pattern C. There were significant differences among the subgroups of patients with different IRF patterns and the control group in LV-ejection fraction, size, wall-motion score index, apical wall-motion score index, systolic and diastolic mitral annular velocities, ratio of the mitral inflow E velocity to early diastolic mitral annular velocity (E/e'), and left atrial diameter (all P < 0.05). In the patient group, a higher wall-motion score index independently predicted the IRF pattern. In patients with severe LV dysfunction, a higher E/e' ratio was the independent predictor of the persistence of a large vortex during the IVR period.

CONCLUSIONS

The IRF pattern is associated with LV function. A large intraventricular vortex persisting during the IVR period should be indicative of increasingly depressed LV function.

Echocardiographic estimation of left ventricular filling pressures in patients with mitral valve stenosis

Background

Estimation of left ventricular end-diastolic pressure (LVEDP) among patients with mitral valve disease may help to explain their symptoms. However, conventional Doppler measurements have limitations in predicting LVEDP in this group of patients. The aim of this study was to construct a Doppler-derived LVEDP prediction model based on the combined analysis of transmitral and pulmonary venous flow velocity curves.

Methods

Thirty-three patients with moderate to severe mitral stenosis (MS) who had indications for left heart catheterisation enrolled. Two-dimensional, M-mode, colour Doppler and tissue Doppler imaging indices, such as annular early diastolic velocity (Ea), isovolumic relaxation time (IVRT), pulmonary vein systolic and diastolic flow velocities, velocity propagation, left atrium area (LAA), interval between the onset of mitral E and annular Ea (TE–Ea), and Tei index were obtained. LVEDP was measured in all patients during left cardiac catheterisation. Linear correlation and multiple linear regressions were used for analysis.

Results

The mean of LVEDP was 9.9 ± 5.3 mmHg. In univariate analysis, the only significant relationship was noted with LAA (p = 0.05, R² = 0.11). However, in multivariate regression, LAA, Tei index and Ea remained in the model to predict LVEDP (p = 0.02, R² = 0.26). For prediction of LVEDP ≥ 15 mmHg, the best model consisted of LAA, IVRT and Ea, and had a sensitivity of 85% and specificity of 85%.

Conclusion

Our results provided evidence that, in patients with moderate to severe MS, LVEDP can be estimated by combining Doppler echocardiographic variables of mitral flow. However, more studies are required to confirm these results.

Left intraventricular diastolic and systolic pressure gradients

To describe left ventricular (LV) function comprehensively, it is crucial to characterize precisely transmitral, intraventricular and transaortic pressure–flow relations. The site of measurement is important; as the measurement location is moved from the mitral valve toward the apex and the outflow tract, important regional pressure differences are recorded inside the LV. These intraventricular pressure gradients (IVPGs) play an important role in ventricular filling in the normal heart and may be abolished by systolic or diastolic dysfunction. Despite their apparent importance in ventricular filling and diastolic function, IVPGs have never been utilized in clinical cardiology, due to the complexity of their acquisition. The application of Doppler echocardiography allows the reconstruction of diastolic IVPGs completely non-invasively, thus avoiding the risk and expense of a cardiac catheterization. Regional pressure gradients are also present during ventricular emptying but their correlation with systolic function is not so clear. The current minireview highlights theories and experimental data on invasive and non-invasive assessment of diastolic and systolic IVPGs and their role in LV filling and emptying. We also review the pathophysiological modulation of regional gradients, their importance in understanding and evaluating the complex phenomena underlying ventricular filling, as well as their potential clinical application.