Regional wall motion abnormalities during early diastole in patients with hypertensive left ventricular hypertrophy: a Doppler tissue echocardiographic study.

To investigate left ventricular wall motion asynchrony in patients with hypertensive heart disease, we measured regional myocardial velocity in hypertensive patients with left ventricular hypertrophy and in normotensive individuals using tissue Doppler imaging. The endocardial velocity and the myocardial velocity gradient were measured in the basal and mid segments of the septal and posterior walls. The dilating velocity of the left ventricular cavity were determined for the basal and mid ventricular segments of left ventricle. The peak myocardial velocity gradient was significantly lower in the hypertensive group than in the control group for all regions. The peak endocardial velocity during early diastole in the mid ventricular septum was significantly lower in the hypertensive group (Hypertensive vs Controls; 3.8 +/- 1.3 vs 5.1 +/1.6 cm/s, P < 0.05), whereas the peak endocardial velocity at the other three sites were similar in the two groups. The peak dilating velocity was significantly lower in the hypertensive group only in the mid portion of the left ventricle (Hypertensive vs Controls; 7.2 +/- 2.4 vs 9.8 +/- 1.3 s(-1), P < 0.005). These results suggest that there were regional wall motion abnormalities and nonuniformity during the early diastolic phase in the hypertensive hearts with left ventricular hypertrophy.

Is arterial remodeling truly a compensatory biological reaction? A mechanical deformation hypothesis.

It has been recognized that arterial enlargement occurs in relation to the formation of atherosclerotic plaque. Previous studies on arterial remodeling have disregarded the role of mechanical deformation and have suggested that compensatory mechanisms occur to maintain arterial flow. We postulated that primary atherosclerotic enlargement and mechanical deformation are the predominant causes of the arterial remodeling. This hypothesis better explains the morphological changes without suggesting additional biological reactions.

Quantitative assessment of diastolic filling function: a new Doppler echocardiographic method and in vitro validation.

The effects of changes in preload and chamber compliance on the transmitral flow pattern was investigated with a fluid dynamics model. A decrease in compliance led to a steepening of the deceleration slope and a shortening of the pressure half-time in both restricted and nonrestricted valves. An increase in the preload led to a longer pressure half-time but did not affect the slope in the restricted valve. However, increased preload led to a shorter pressure half-time and a steeper slope in the nonrestricted valve. A mathematically derived method to measure the net atrioventricular compliance (-[annular area] va/[pvt [flow deceleration rate]]), where va and vt are flow velocities at the mitral anulus and the mitral tip levels) was then proposed. The values obtained by this method showed a strong correlation with true values (r2 = 0.89). A possibility of noninvasive quantitative assessment of diastolic filling function was implied.

Effects of dobutamine on left ventricular diastolic performance are attenuated in patients with systemic hypertension.

We measured Doppler echocardiographic diastolic parameter during infusion of low-dose dobutamine in 14 untreated hypertensive subjects and in 14 normal controls. Low-dose dobutamine accelerated left ventricular relaxation in normal controls but not in hypertensive subjects.

Transesophageal echocardiographic recognition of a fistula between a coronary artery and the left atrium.

A 58-year-old woman with a prosthetic mitral valve and an anomalous single coronary artery received transesophageal echocardiography and was found to have a coronary artery--to--left atrium fistula. Because of its superior imaging quality, transesophageal color Doppler method is a useful diagnostic procedure.

Enhanced flow velocity increase through the left ventricular inflow tract of patients with isolated aortic regurgitation.

Twenty-five patients with chronic aortic regurgitation (AR), and 12 control subjects were studied using Doppler echocardiography to investigate the effects of AR on transmitral flow. Peak early filling velocities at the levels of the mitral valve tips (E1) and annulus (E2) were measured, and the transmitral flow restriction index (delta E = (E1-E2)/E2) was obtained. Patients with AR were classified into 2 groups according to the ratio of the cross-sectional area of the regurgitant jet to that of the left ventricular outflow tract. Group I had the ratio less than 0.20, and group II had greater than or equal to 0.20. E2 in group II was lower than in control subjects, whereas E1 was not significantly different in any groups. delta E in group II was higher than in group I or in control subjects (p less than 0.05 and 0.01, respectively). delta E showed a significant correlation with the cross-sectional area ratio in all patients with AR (r = 0.70, p less than 0.01) and in group II (r = 0.82; p less than 0.01). Our data suggest that AR restricts early transmitral filling, and that delta E may indicate the increased driving pressure caused by flow restriction and is a useful hemodynamic index of AR.

[Prosthetic valve function evaluated by ultrafast computed tomography (Imatron C-100)].

Ultrafast computed tomography (UFCT) is a new diagnostic modality that includes not only imaging of cardiac structures, but also movement of cardiac muscles and valves. It can be useful in the evaluation of prosthetic valves, because the scan time is extremely short and whole cardiac structures are imaged with a slice thickness of 8 mm and within 7 cardiac cycles. We review our experience using UFCT to observe prosthetic valve function in 22 cases with various valvular diseases.