The Influence of The Left Ventricular wall Thickness on The Pulmonary Venous Flow Mechanics in Hypertrophied Heart--A Study with Transesophageal Pulsed Doppler Echocardiography

Abstract

Although syncope and sudden cardiac death were regarded as the results of left ventricular outflow tract obstruction caused by powerful left ventricular contraction in patients with hypertrophic cardiomyopathy, it is now widely appreciated that the clinical manifestations such as chest pain, dyspnea and heart failure are the main problems which are produced by disorders in diastole.

It is convenient to use transthoracic transmitral flow echocardiography for clinical assessment of LV diastolic dysfunction, however, with progressively compensatory dilation of LV chamber, it became difficult to assess LV diastolic function with Transmitral flow pattern owing to its pseudonormalization pattern change.

In order to evaluate the clinical significance of ventricular wall thickness on pulmonary venous flow pattern, transesophageal pulsed Doppler echocardiography (TEE) was performed in 12 patients with HCM, 11 well-controlled hypertensive patients and 15 normal controls ( total 38 individuals). Parameters were obtained from pulmonary venous flow (PVF) pattern and transmitral flow (TMF) pattern in TEE initially; secondary, these data of TMF pattern were compared with that of TMF pattern in transthoracic pulsed Doppler echocardiography (TTE).

Results were as follows:

1. Peak velocity of forward diastolic flow wave (D-wave) of Pulmonary Venous flow (PVF) pattern in HCM cases was significantly decreased in comparison with values in normal controls(0.36+/-0.10 VS. 0.52+/-0.19 m/s, p<0.05).

2. Mitral annular descents (MAD) in HCM & hypertensive groups had significant values than that in normal controls(6.3+/-3.0; 5.4+/-2.8 VS. 9.8+/-4.1 mm respectively, p<0.01).

3. In patients with HCM, isovolumic relaxation time (IVRT) of TMF pattern, either from TTE or from TEE measurement, were longer than those in normal controls(140+/-37 VS. 107+/-29; 134+/-30 VS. 105+/-24 msec. respectively, p<0.05).

4. In the PVF pattern of HCM cases, there was a enhanced forward mid-diastolic flow (MDF) wave following a decreased D-wave presented, which was coincided in timing with MDF wave of TMF pattern (either TTE or TEE measurement).

5. In cases of HCM, PVF pattern showed a tiny early systolic retrograde (SR) wave which was coincided with QRS wave of ECG monitoring during Doppler mapping.

6. There was a negative correlation between the peak velocity of D-wave of PVF pattern and the mean thickness of left ventricular wall. (r=-0.58, p=0.0002).

Our study suggested that PVF pattern can be one mode of LV diastolic dysfunction assessments in patients with hypertrophied heart. whether MDF wave of PVF pattern or the appearance of hexaphasic PVF pattern could be a marker of LV diastolic dysfunction in clinical application is still a question which needs further evaluation.