| IntroductionLeft ventricular diastolic dysfunction has been recognized as an important primary cause of heart failure. Studies on left ventricular diastolic function (LVDF) in hypertensive patients have shown that diastolic dysfunction occurs earlier than LVH or systolic dysfunction. Parameters obtained from the transmitral flow velocity pattern correlated closely with those obtained by left ventriculography and radionuclide angiography. Therefore, the transmitral flow velocity pattern is widely used to evaluate LVDF in clinical settings. However, because it is influenced strongly by loading condition, there is a limitation when this index is used in patients with elevated left ventricular (LV) end -diastolic pressure. Doppler tissue imaging (DTI) is a new technique to evaluate the global LVDF by measuring mitral annulus velocity and is expected to provide valuable information on LV wall motion abnormalities in patients with heart disease. As a noninvasive preload - independent index of LV relaxation, it could discriminate pseudonormal from normal diastolic function, establish prognosis, and evaluate the effect of therapeutic interventions.Carvedilol can block all three adrenergic receptors (α1, β1 and β2) , exhibit peripheral vasodilating actions, suppresse cardiac sympathetic overactivity in patients with essential hypertension. The present study was designed to evaluate the effect of carvedilol on LV dias-tolic dysfunction in hypertensive patients with DTI methods.MethodsSubjects71 mild - moderate essential hypertension patients without left ventricular systolic dysfunction and left ventricular dilation ( LVEF > 50% and LVDd <55mm men or <50mm women) age 37 -65 were included. Heart rate(HR) was between 60 -90bpm. Secondary hypertension, coronary heart disease, diabetes mellitus, significant valvular heart disease or liver and renal failure were excluded. Patients were divided into LVH and nori - LVH groups according to LVMI >125g/m2(men) or>110 g/m2 ( women). Among them, 33 patients have LVH. There were 20 normotensive healthy subjects as control.Study ProtocolLVDF and blood pressure ( BP) were checked in all enrolled subjects . Carvedilol was administered to the patients with E/A < 1 obtained by Doppler flow imaging and Ea/Aa < 1 by DTI at a daily dose of lOmg - 20mg for 12weeks. BP and HR were regularly checked at 2, 4 and 12 weeks after the treatment. At the end of 12 weeks, E, A and Ea ,Aa were measured respectively.LVDF measurement : From the apical four - chamber view, a sample volume was set at the lateral corner of the mitral annulus. The motion velocity patterns were recorded by DTI. Subsequently, the flow velocity pattern were recorded by placing the sample volume at the mitral valve tips , and using pulsed Doppler echocardiography for 3 cardiac cycles at a sweep speed of 100 mm/s. The mean of 3 consecutive heart beats was used for each measurement.Statistical AnalysisData were expressed as X ?SD. Comparisons among the 3 groups ( control, LVH and non - LVH groups) were performed by analysis of variance followed by t test. A paired t test was performed before and after treatment. P<0.05 were considered significant.ResultsBasal charactersticsThere were no significant differences in age, sex, body mass and heart rate in basal state between hypertensive patients and control subjects.The study showed Ea and Ea/Aa ratio in hypertensive patients were lower than those of normal control( P <0. 01) . These two indices in patients with LVH were lower than those in non - LVH( P <0. 05). E and E/A ratio in patients are lower than those in control (P < 0. 01), but there was no significant difference between LVH group and non - LVH group ( P > 0. 05). Aa had no significant difference with normal subjects, but A in patients group was higher than that of control (P <0. 01) . The Ea/Aa ratio related weU to E/A ratio in normal and non - LVH groups( r = 0. 80 and 0. 76, P < 0.01) , while no correlated relationship was found between LVH and non -LVH groups (r... |
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