Using our database of the patients who underwent transthoracic echocardiography between January 2004 and December 2007, we selected 181 patients, among all the hypertensive patients, for analysis and these 181 patients' clinical and echocardiographic data were readily available. Patients were defined as being hypertensive if they had a history of antihypertensive therapy, an office systolic blood pressure ≥140 mmHg or a diastolic blood pressure ≥90 mmHg. The prior medications consisted of calcium antagonists, diuretics, beta-blockers, angiotensin converting enzyme inhibitors and angiotensin receptor blocker. We excluded all the individuals with established cardiovascular diseases such as myocardial infarction, angina, coronary bypass grafting and congestive heart failure, atrial fibrillation, significant aortic and/or mitral valve disease, or an ejection fraction <50%. Based on the LVMI and the RWT, the patients were categorized into four groups: the normal geometry group, the concentric remodeling group, the eccentric hypertrophy group and the concentric hypertrophy group.

Transthoracic echocardiography was performed using a commercially available imaging ultrasound system (Sonos 5500, Hewlett-Packard Co., Palo Alto, CA, USA) with harmonic imaging. The measurements were made according to the recommendations of the American Society of Echocardiography and using the leading edge to leading edge convention.6) The left ventricular internal dimension, the septal thickness and the left ventricular posterior wall thickness were measured at end-diastole as defined by the onset of the QRS complex. The RWT was calculated as follows: 2×left ventricular posterior wall thickness/left ventricular end-diastolic dimension. A value more than 0.44 was defined as abnormal. The left ventricular mass was calculated using the formula developed by Devereux et al.8): 0.80×1.04 {(left ventricular end-diastolic diameter+left ventricular septal thickness+posterior wall thickness)³-(left ventricular end-diastolic diameter)³}+0.6. The LVMI was indexed for the body surface area. Left ventricular hypertrophy was to be considered present when the LVMI was >125 g/m² in men or >110 g/m² in women.9) The combination of the LVMI and RWT defined the four left ventricular geometric patterns: normal geometry (a normal LVMI and a normal RWT), concentric remodeling (a normal LVMI and an increased RWT), concentric hypertrophy (an increased LVMI and an increased RWT) and eccentric hypertrophy (an increased LVMI and a normal RWT).1) The left atrial diameter was measured by the two-dimensional guided M-mode echocardiography obtained with the parasternal short-axis view at the base of the heart.7) The left atrial volume was calculated from the apical four-chamber and two-chamber views at ventricular end systole with using Simpson's biplane method.10)

The mitral inflow velocities were obtained by pulsedwave Doppler during quiet respiration in the apical fourchamber view with a 1-2 mm sample volume placed at the tips of the mitral valve leaflets. The mitral early (E) and late (A) inflow velocities and the deceleration time (DT) of the E velocity were measured (Fig. 1A). The isovolumic relaxation time was measured by continuouswave Doppler as the time from the closing click of the aortic valve to the onset of transmitral inflow. The pulsedwave Doppler tissue imaging velocities were obtained from the apical four-chamber view during quiet respiration by placing a sample volume in the septal mitral annulus. Images of the left ventricle in the apical four-chamber view were chosen to minimize the angle of incidence between the scan lines and the motion of the lateral mitral annulus. The peak early (E') and late (A') diastolic mitral annular velocities were measured from the time-myocardial velocity waveform, and we calculated the septal E/E' ratio, which is a measure of the left ventricular filling pressure (Fig. 1B). The patients were classified into four different stages of diastolic function: 1) normal filling was defined as a DT greater than or equal to 140 milliseconds and less than 240 milliseconds, an E/A ratio between 1.0 and 2.0 and an E'/A' ratio above 1.0; 2) abnormal relaxation was defined as a DT above 240 milliseconds, an E/A ratio less than 1.0 and an E'/A' ratio less than 1.0; 3) pseudonormal filling was defined as a DT greater than or equal to 140 milliseconds and less than 240 milliseconds, an E/A ratio between 1.0 and 2.0 and an E'/A' ratio less than 1.0; and finally 4) restrictive filling was defined as a DT less than 140 milliseconds.

The data was analyzed using Statistical Package for Social Science (SPSS) 14.0 software (SPSS, Chicago, IL, USA). The variables are expressed as means±standard deviations. The continuous variables were compared by one-way analysis of variance followed by the Tukey post hoc test for multiple comparisons. Proportions were compared among groups by chi-square analysis. Statistical significance was defined as p<0.05.

The demographic characteristics of the study population are shown in Table 1. The four groups of patients that were characterized by the different left ventricular geometric patterns had a similar gender distribution and prevalence of diabetes, although the patients with left ventricular hypertrophy had a lower mean age than did the patients with normal geometry. The body mass index was lower in the eccentric hypertrophy group as compared with all the other groups. The patients with concentric hypertrophy had substantially elevated systolic blood pressure.

The two-dimensional echocardiographic variables are shown in Table 2. By definition, the left ventricular mass was increased in the groups with eccentric and concentric hypertrophy. As compared with the normal geometry group, the left ventricular end-systolic diameter and the left ventricular end-diastolic diameter were significantly reduced in the concentric remodeling group, whereas the left ventricular end-systolic diameter and the left ventricular end-diastolic diameter were increased in the eccentric and concentric hypertrophy groups. The patients with both eccentric and concentric hypertrophy demonstrated significantly higher values for the left atrial diameter and the left atrial volume index (Fig. 2).

The Doppler indices are shown in Table 3. There were no significant differences among any of the four groups in terms of the A velocity, the isovolumic relaxation time and the E' velocity. The E velocity was increased and the A' velocity was decreased in the groups with eccentric and concentric hypertrophy, as compared with those values of the normal geometry group. The DT was lower in the eccentric hypertrophy group, as compared with that of the other groups.

The E/E' showed a significant stepwise increase from the normal geometry group to the concentric remodeling group and then to the eccentric and concentric hypertrophy groups (Fig. 3). The differences of the diastolic filling pattern, as assessed by the mitral inflow, among the groups showed borderline significance (p=0.064).

The major limitation of the current investigation is that it was a cross-sectional study and the data was obtained retrospectively by a review of the patients' records and echocardiograms rather than gathering the data prospectively, although the echocardiograms were reviewed without the reviewer having any knowledge of the clinical and hemodynamic data. The duration of hypertension and antihypertensive medication was not certain for some patients. Yet most of the patients were taking more than two types of drugs, so the effect of any specific drug on cardiac remodeling and the diastolic function could be minimized. The patients with concentric hypertrophy had elevated systolic blood pressure, as compared with the patients who had normal geometry, and this fact might have influenced the results. The differences in the left atrial volume index and the E/E' between the group of patients with concentric hypertrophy and the group of patients with eccentric hypertrophy were not statistically significant, so further studies with larger patient groups are needed to compare these two groups.

This study demonstrates that in a patient population with hypertension and without systolic dysfunction, both the left atrial volume index and the E/E' demonstrate progressive worsening of the left ventricular diastolic function in the order of the patients with normal geometry to the patients with concentric remodeling and to the patients with eccentric and concentric hypertrophy.