161 resultados para Systolic function

em University of Queensland eSpace - Australia


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OBJECTIVES We sought to determine if a hypertensive response to exercise (HRE) is associated with myocardial changes consistent with early hypertensive heart disease. BACKGROUND An HRE predicts the development of chronic hypertension (HT) and may reflect a preclinical stage of HT. METHODS Patients with a normal left ventricular (LV) ejection fraction and a negative stress test were recruited into three matched groups: 41 patients (age 56 +/- 10 years) with HRE (210/105 mm Hg in men; > 190/105 in women), comprising 22 patients with (HT+) and 19 without resting hypertension (HT-); and 17 matched control subjects without HRE. Long-axis function was determined by measurement of the strain rate (SR), peak systolic strain, and cyclic variation (CV) of integrated backscatter in three apical views. RESULTS An HRE was not associated with significant differences in LV mass index. Exercise performance and diastolic function were reduced in HRE(HT+) patients, but similar in HRE(HT-) patients and controls. Systolic dysfunction (peak systolic strain, SR, and CV) was significantly reduced in HRE patients (p < 0.001 for all). These reductions were equally apparent in patients with and without a history of resting HT (p = NS) and were independent of LV mass index and blood pressure (p < 0.01). CONCLUSIONS An HRE is associated with subtle systolic dysfunction, even in the absence of resting HT. These changes occur before the development of LV hypertrophy or detectable diastolic dysfunction and likely represent early hypertensive heart disease. (C) 2004 by the American College of Cardiology Foundation.

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B-type natriuretic peptide (BNP) levels increase in systolic heart failure (HF). However, the value of BNP in hypertensive patients with suspected diastolic HF (symptoms suggestive of HF but normal ejection fraction) and its relation to myocardial function in these patients is unclear. We prospectively studied 72 ambulatory hypertensive subjects (40 women, mean age 58 +/- 8 years) with exertional dyspnea and ejection fraction greater than or equal to50%. Diastolic function was evaluated with transmitral and pulmonary venous Doppler, mitral annular velocities (pulsed-wave tissue Doppler), and flow propagation velocity (color M-mode). Systolic function was assessed with strain and strain rate derived from color tissue Doppler imaging. BNP was related to myocardial function and the presence or absence of global diastolic dysfunction. By conventional Doppler criteria, 34 patients had normal left ventricular diastolic function and 38 had isolated diastolic dysfunction. BNP values were higher in patients with diastolic dysfunction (46 +/- 48 vs 20 +/- 20 pg/ml, p = 0.004) and were related independently to blood pressure, systolic strain rate, left atrial function (p < 0.01 for all), and age (p = 0.015). Patients with diastolic dysfunction and pseudonormal filling had higher BNP levels compared with impaired relaxation (89 +/- 47 vs 35 +/- 42 pg/ml, p = 0.001). However, 79% of patients with diastolic dysfunction had BNP levels within the normal range. We conclude that in ambulatory hypertensive patients with symptoms suggestive of mild HF and normal ejection fraction, BNP is related to atrial and ventricular systolic parameters, blood pressure, and age. Although elevated in the presence of diastolic dysfunction, the BNP level mostly is in the normal range and, therefore, has limited diagnostic value in stable patients with suspected diastolic HF. (C) 2003 by Excerpta Medica, Inc.

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Background Previous work suggesting a better correlation of diastolic than systolic function with exercise capacity in heart failure may reflect the -relative insensitivity and load-dependence of ejection fraction (EF). We sought the correlation of new and more sensitive methods of quantifying systolic and diastolic function and filling pressure with functional capacity. Methods We studied 155 consecutive exercise tests on 95 patients with congestive heart failure (81 male, aged 62 +/- 10 years), who underwent resting 2-climensional echocardiography and tissue Doppler imaging before and after measurement of maximum oxygen uptake (peak VO2)Results The resting EF was 3 1 % 10% and a peak VO(2)was 13 +/- 5 mL/kg/min; the majority of these patients (80%) had an ischemic cardiornyopathy. Resting EF (r 0.14, P =.09) correlated poorly with peak VO2 and mean systolic (r = 0.23, P =.004) and diastolic tissue velocities (r 0.18, P =.02). Peak EF was weakly correlated with the mean systolic (r = 0.18, P =.02) and diastolic velocities (r = 0.16, P <.04). The mean sum of systolic and diastolic velocities in both annuli (r = 0.30, P <.001) and E/Ea ratio (r 0.31, P <.001) were better correlated with peak VO2 Prediction of peak VO2 was similar with models based on models of filling pressure (R = 0.61), systolic factors (R = 0.63), and diastolic factors (R 0.59), although a composite model of filling pressure, systolic and diastolic function was a superior predictor of peak VO2 (R 0.69; all P<.001). Conclusions The reported association of diastolic rather than systolic function with functional capacity may have reflected the limitations of EF. Functional capacity appears related not only to diastolic function, but also to systolic function and filling pressure, and is most closely associated with a combination of these factors.

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1. Evidence from recent experimental and clinical studies suggests that excessive circulating levels of aldosterone can bring about adverse cardiovascular sequelae independent of the effects on blood pressure. Examples of these sequelae are the development of myocardial and vascular fibrosis in uninephrectomized, salt-loaded rats infused with mineralocorticoids and, in humans, an association of aldosterone with left ventricular hypertrophy, impaired diastolic and systolic function, salt and water retention causing aggravation of congestion in patients with established congestive cardiac failure (CCF), reduced vascular compliance and an increased risk of arrhythmias (resulting from intracardiac fibrosis, hypokalaemia, hypomagnesaemia, reduced baroreceptor sensitivity and potentiation of catecholamine effects). 2. These sequelae of aldosterone excess may contribute to the pathogenesis and worsen the prognosis of CCF and hypertension. 3. The heart and blood vessels may be capable of extra-adrenal aldosterone biosynthesis, raising the possibility that aldosterone may have paracrine or autocrine (and not just endocrine) effects on cardiovascular tissues. 4. The high prevalence of CCF, which is associated with secondary aldosteronism, and primary aldosteronism (PAL; recently recognized to be a much more common cause of hypertension than was previously thought) argue for an important role for aldosterone excess as a cause of cardiovascular injury. 5. The recognition of non-blood pressure-dependent adverse sequelae of aldosterone excess raises the question as to whether normotensive individuals with PAL, who have been detected as a result of genetic or biochemical screening among families with inherited forms of PAL, are at excess risk of cardiovascular events. 6. Provided that patients are carefully investigated in order to permit the appropriate selection of specific surgical (laparoscopic adrenalectomy for PAL that lateralizes on adrenal venous sampling) or medical (treatment with aldosterone antagonist medications) management and safety considerations for the use of aldosterone antagonists are kept in mind, the appreciation of a widening role for aldosterone in cardiovascular disease should provide a substantially better outlook for many patients with CCF and hypertension.

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Abnormal left ventricular (LV) filling is common, but not universal, in hypertensive LV hypertrophy (LVH). We sought to elucidate the relative contributions of myocardial structural changes, loading and hypertrophy to LV dysfunction in 113 patients: 85 with hypertensive LVH and 28 controls without LVH and with normal filling. Patients with normal dobutamine stress echocardiography and no history of coronary artery disease were selected, in order to exclude a contribution from ischaemia or scar. Abnormal LV filling was identified in 65 LVH patients, based on Doppler measurement of transmitral filling and annular velocities. All patients underwent grey-scale and colour tissue Doppler imaging from three apical views, which were stored and analysed off line. Integrated backscatter (113) and strain rate imaging were used to detect changes in structure and function; average cyclic variation of 113, strain rate and peak systolic strain were calculated by averaging each segment. Calibrated 113 intensity, corrected for pericardial 113 intensity, was measured in the septum and posterior wall from the parasternal long-axis view. Patients with LVH differed significantly from controls with respect to all backscatter and strain parameters, irrespective of the presence or absence of abnormal LV filling. LVH patients with and without abnormal LV filling differed with regard to age, LV mass and incidence of diabetes mellitus, but also showed significant differences in cyclic variation (P < 0.01), calibrated 113 in the posterior wall (P < 0.05) and strain rate (P < 0.01), although blood pressure, heart rate and LV systolic function were similar. Multivariate logistic regression analysis demonstrated that age, LV mass index and calibrated IB in the posterior wall were independent determinants of abnormal LV filling in patients with LVH. Thus structural and functional abnormalities can be detected in hypertensive patients with LVH with and without abnormal LV filling. In addition to age and LVH, structural (not functional) abnormalities are likely to contribute to abnormal LV filling, and may be an early sign of LV damage. 113 is useful for the detection of myocardial abnormalities in patients with hypertensive LVH.

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Background. Regional left ventricular (LV) dysfunction may occur in patients with coronary artery disease (CAD) in the absence of infarction, but the causes of this phenomenon are unclear. We sought to identify whether changes in regional LV function were related to stenosis severity, using sensitive new ultrasound markers of function. Methods: We studied 67 individuals with no history of infarction and with normal LV systolic function: 49 patients with CAD and 18 control subjects without CAD. All patients underwent color Doppler tissue imaging, integrated backscatter (IB), anatomic M-mode echocardiography, and strain rate imaging to detect changes in structure and function. Peak early and late diastolic myocardial velocity, cyclic variation of IB, wall thickness, and percent wall thickening were measured in each basal and mid segment. Strain rate and peak systolic strain were calculated in each wall. CAD was defined as greater than or equal to 50% diameter stenosis. Normokinetic segments (n = 354) subtended by CAD were divided according to stenosis severity into 3 groups: group 1 (subtended by 50%-69% stenosis); group 2 (subtended by 70%-98% stenosis); and group 3 (subtended by greater than or equal to99% stenosis). Each parameter in each group was compared with that in 216 segments from control subjects. Results: Segments subtended by significant CAD showed lower peak early and late diastolic myocardial velocity compared with control segments. Group 3 showed significantly lower myocardial velocities than group 2 for both peak early (4.8 +/- 1.8 vs 6.0 +/- 2.0 cm/s, P