The Hypertensive Influence On Left Ventricular Diastolic Function

Background:Hypertension, when sustained over years espresses serious disabling consequences such as heart failure, stroke, ischaemic heart disease and renal failure. In the natural course of hypertensive heart disease, diastolic dysfunction occurs before systolic dysfunction. Differences exist between diastolic and systolic heart failure in terms of the predominant pathophysiological mechanism, therapeutic method and prognosis. It is very important to discover and diagnosis diastolic dysfunction of hypertensive patients timely in clinical practice. Currently the most common method to determine diastolic dysfunction is ultrasonic Doppler, which is simple and noninvasive. But its accuracy depends on heart rate, cardiac load and something else. Besides, there may be "Pseudo normal phenomenon". Doppler tissue imaging (DTI) is a new method of testing cardiac diastolic function in recent years. Some research shows that DTI can discover systolic and diastolic dysfunction in the early stage of patients with hypertension, especially the diastolic function. DTI is not affected by the cardiac preload and afterload, and can avoid "pseudo normal phenomenon".Objective:To evaluate the clinically applied value of the Tissue Doppler Imaging and Pulse Wave Doppler, which are used to assess left ventricular diastolic function of hypertensive patients grouped by New York Heart Association (NYHA) in order to find a reliable and objective method to assess the left ventricular diastolic function of hypertensive patient.Methods:100 hypertensive patients in our hospital between December 2008 and October 2009 were recruited into the study. The patients whose age was between 47 and 78, averaged 63.27±8.15, and whose duration of hypertension was between 10 years and 25 years, were diagnosed according to World Health Organization (WHO) diagnostic standard of hypertension in 1999. Coronary disease, valvular heart disease, diabetes, kidney disease, serious arrhythmia and some other disease which could affect cardiac diastolic function were excluded.100 patients were divided into four groups according to cardiac function standard of New York Heart Association (Ⅰ:the physical exercise is unconstrained, daily activity can not cause clinical symptoms;Ⅱ:the physical exercise is constrained slightly, general activity can cause frailty,palpitate, dyspnea and so on;Ⅲ:the physical exercise is constrained obviously, mild activity can frailty, palpitate,dyspnea and so on;Ⅳ:the physical exercise is constrained seriously, patients can not do any activity, even if at rest they may have heart failure symptoms and signs) There are 30 patients with cardiac functional capacity classificationⅠ,25 with cardiac functionⅡ,25 with cardiac functionⅢ,20 with cardiac functionⅣ. 100 hypertension patients were assessed echocardiographically using ultrasound cardiogram at first. M-Mode measurements were taken in the level of left ventricle(LV) chordae tendinca. Measurements taken were interventricular septal thickness(IVSd), LV posterior wall thickness(LVIDd), and internal dimension in both diastole(LVPWd) and systole(LVIDs). LV ejection fraction (EF) were calculated by the machine using biplane meliorative Simpson method in the apical four-chamber section. The E and A wave velocities of mitral inflow were measured from pulsed wave Doppler (PWD) of mirtal inflow velocity tracing and the E/A ratio was calculated. The e and a wave velocities of Mitral valve annulus movement were taken from Tissue Doppler Imaging(DTI) and the e/a ratio was calculated.Result:1.The four groups of patients were well matched with regard to baseline characteristics of age, gender, body surface area (BSA), and systolic pressure (SBP), diastolic pressure (DBP), disease duration and medicine (P>0.05).2. In terms of parameter measured by routine examination, such as LVIDs,LVIDd,IVSd,LVPWd, there was no significant left ventricular hypertrophy in groupⅠandⅡ(P>0.05). But the parameter of groupⅢandⅣwere increased (P<0.05).The left ventricular ejection fraction were reduced gradually from groupⅠto groupⅣ(P<0.05).3.There were no statistically significant difference between the groups in terms of E value (P<0.05). Compared to groupⅠ, E value in groupⅢwas significantly reduced (P<0.05,0.94cm/sVS 0.95cm/s), which was significantly increased in groupⅡ(P<0.05,0.94cm/s VS 0.66cm/s). E/A ratio is reduced in gradeⅢcompared to gradeⅠ(P<0.05),but is increased compared to gradeⅡ(P<0.05)4.1n terms of parameter measured by DTI, all of the e/a<1, e value of groupⅡ,Ⅲ,Ⅳ(7.40cm/s,6.45cm/s,6.21cm/s) were less than that of groupⅠ(8.73cm/s, P<0.05). In groupⅡandⅣ,the a value(12.55 cm/s,12.08cm/s) had increased significantly compared to that in groupⅠ(10.35 cm/s, P<0.05). Compared to groupⅡandⅢ(12.55cm/s,12.08cm/s), the a value in groupⅣ(15.07cm/s) had increased significantly(P<0.05). Compared to gradeⅠ,e/a ratio had reduced in gradeⅡ,ⅢandⅣ(P<0.05). e/a ratio in gradeⅣis lower than that in gradeⅡandⅢ(P<0.05).The positive rate of DTI is higher than that of PWD (P<0.05)Conclusion:Hypertension can cause left ventricular diastolic dysfunction, which can occur before left ventricular hypertrophy, and with clinical cardiac symptoms progressing, the ventricular diastolic function was worsen. DTI is more sensitive than PWD in the field of evaluation left ventricle diastolic function. It can differentiate the "pseudo normalized" of PWD.