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Effects of changes in afterload impedance on left ventricular ejection in isolated canine hearts: dissociation of end ejection from end systole.

To examine how end systole differs from end ejection and also whether the slope of the end systolic pressure-volume relation can be approximated to that of the end ejection pressure-volume relation, nine isolated, perfused, paced canine hearts ejecting into a hydraulic loading system that simulated the aortic input impedance of a dog's arterial tree were studied. To measure left ventricular volume changes the heart was placed in a plethysmograph. Peripheral resistance (Rp) and arterial compliance (C) were independently varied from 1.9 (Rp = 1.9) to 3.3, 6.4, and 9.6 X 10(8) Pa.m-3.s (Rp run) with a constant value of compliance 1.3 X 10(-9) Pa-1.m3 (C = 1.3), and from C = 0.4 to C = 0.8, C = 1.3 and C = 2.3 (C run) with a constant value of resistance (Rp = 6.4). Five pressure-volume loops were obtained by changing the end diastolic volume at each value of compliance and peripheral resistance. It was clearly shown that ventricular ejection continued after end systole and the time duration between end systole and end ejection became longer with increasing arterial compliance (24(4) at C = 0.4 vs 49(4) ms at C = 2.3, p less than 0.001), while the time duration between end diastole and end systole was constant regardless of afterload impedance change. Regarding the left ventricular pressure-volume relation the end systolic relation was almost linear (r greater than or equal to 0.98) and the slope was not significantly affected by change in any afterload impedance tested. End ejection pressure-volume relation was also linear (r greater than or equal to 0.97) and the slopes in the peripheral resistance and compliance runs were lower than those of the end systolic pressure-volume relation in each corresponding run. The former slopes decreased at smaller values of Rp or larger values of C--namely, 4.4(0.6) at Rp = 9.6 vs 3.6(0.6) at Rp = 1.9, p less than 0.05; 4.8(0.6) at C = 0.4 vs 3.1(0.5) mmHg.ml-1 at C = 2.3, p less than 0.001. Thus it is concluded that end ejection is usually different from end systole and the time difference between them is affected by changes in arterial compliance. In addition, the slope of end ejection pressure-volume relation was dependent on the changes in afterload impedance and cannot be approximated to that of the end systolic pressure-volume relation.

Animals↗

Non-invasive assessment of end-systolic pressure-length and stress-shortening relationships in normal individuals: significance of different loading conditions induced by methoxamine and angiotensin II.

To evaluate whether the end-systolic pressure-dimension and stress-shortening relations are influenced by the drugs used for their assessment, we analysed the effects of angiotensin II (N = 30) and methoxamine (N = 10) in normal individuals. Serial measurements of left ventricular dimensions and wall thickness were performed by M-mode echocardiography; the end-systolic pressure was assessed by indirect, calibrated carotid pulse tracings. The end-diastolic dimension, which reflects preload, remained unchanged during the afterload challenge using angiotensin II, but increased significantly using methoxamine (P less than 0.001). Significant differences due to the agent used were observed for the end-systolic pressure-dimension relationship (P less than 0.002), the relation between end-systolic wall stress and fractional shortening (P less than 0.0002), and the relation between end-systolic wall stress and mean fibre shortening velocity (P less than 0.02). The extrapolated end-systolic dimension D0 at zero end-systolic pressure was significantly shifted to the left when using angiotensin II (P less than 0.02); this is considered to be due to its negligible effect on preload. Our data suggest that the assessment of the end-systolic pressure-dimension and stress-shortening relationships depends significantly on drug specific effects and the variation of preload during the afterload challenge. Based on these results, the use of angiotensin II is emphasized for the assessment of the end-systolic pressure-dimension and stress-shortening relationships.

Adult↗

Effect of jet ventilation on heart failure: decreased afterload but negative response in left ventricular end-systolic pressure-volume function.

OBJECTIVE: To examine the mechanism of cardiac assist with systolic jet ventilation, specifically effects on loading conditions and left ventricular pressure-volume function. Both systolic and diastolic jet ventilation were compared in the absence and presence of heart failure. DESIGN: Prospective, two-factor, repeated-measures study. SETTING: Animal laboratory. SUBJECTS: Ten anesthetized, closed-chest dogs. INTERVENTIONS: The measurement protocol consisted of two phases: a) apnea, randomized jet ventilation (systole- and diastole-synchronized); b) postjet ventilation apnea, before and after heart failure, induced with a propranolol-imipramine-plasma expansion treatment. MEASUREMENT AND MAIN RESULTS: Systolic and diastolic jet ventilation was associated with mean airway pressures of approximately 7 mm Hg and intrapleural pressures of approximately 3 mm Hg in both heart conditions. In normal hearts, jet ventilation (either mode) decreased transmural left ventricular end-diastolic pressure by 40% to 60% (p < .05), left ventricular end-diastolic volume 25 +/- 8%, and stroke volume by 28% to 30%. Heart failure was associated with decreases (41 +/- 6%) in end-systolic pressure-volume function (i.e., pressure change/volume change or elastance), transmural left ventricular end-systolic pressure (22 +/- 3%), and stroke volume (16 +/- 4%), and increased transmural left ventricular end-diastolic pressure (139 +/- 6%). Application of jet ventilation (either mode) during heart failure did not affect stroke volume but significantly (p < .05) attenuated transmural left ventricular end-diastolic pressure by 30% to 40%, left ventricular end-diastolic volumes by 33 +/- 9%, and transmural left ventricular end-systolic pressure by 11% to 19% (p < .05). After jet ventilation, left ventricular elastance was decreased 36 +/- 8% in normal hearts and 35 +/- 11% in failing hearts. Stroke volume, however, returned to baseline levels because of increases in transmural left ventricular end-diastolic pressure in both heart conditions, and also in failing hearts, because transmural left ventricular end-systolic pressure remained decreased approximately 30% (p < .05). CONCLUSIONS: Jet ventilation did not decrease stroke volume in failing hearts because of the afterload-reducing benefit (decreased transmural left ventricular end-systolic pressure) of increased intrapleural pressure in dilated ventricles. Moreover, jet ventilation did not have positive effects on myocardial function and had negative effects on left ventricular elastance in the postjet ventilation period in both normal and failing hearts. Cardiac assist by jet ventilation was not cycle specific, suggesting no selective benefit of jet ventilation over conventional positive-pressure ventilation during heart failure. These studies demonstrate a negative inotropy associated with jet ventilation that, during heart failure, may compromise the general benefit of positive-pressure-mediated increases in intrapleural pressure.

Adrenergic Uptake Inhibitors↗

Systolic blood pressure in babies of less than 32 weeks gestation in the first year of life. Northern Neonatal Nursing Initiative.

AIM: To define the normal range of systolic blood pressure in a non-selective population based sample of babies of low gestation throughout early infancy. METHODS: Daily measurements of systolic blood pressure were made in all the babies of less than 32 weeks gestation born in the North of England in 1990 and 1991 during the first 10 days of life. Additional measurements were obtained from 135 of these babies throughout the first year of life. Systolic pressure was measured by sensing arterial flow with a Doppler ultrasound probe. It was assumed that blood pressure had never been pathologically abnormal in the neonatal period if the child was alive and free from severe disability two years later. Data of adequate quality were available from 398 such children. Additional data wer collected, for comparative purposes, from 123 babies of 32, 36, or 40 weeks of gestation. RESULTS: Systolic pressure correlated with weight and gestation at birth, and rose progressively during the first 10 days of life. The coefficient of variation did not vary with gestational or postnatal age (mean value 17%), the relation with gestation being closer than with birthweight. Systolic pressure rose 20% during the first 10 days from an initial mean of 42 mm Hg in babies of 24 weeks gestation, and by 42% from an initial mean of 48 mm Hg in babies of 31 weeks gestation. These findings were not altered by the exclusion of data from 14 babies who had inotropic support during this time. Simultaneous measurements in three centres using an oscillometric technique revealed that this technique tended to overestimate systolic pressure when this was below average. Systolic pressure finally stabilised at a mean of 92 (95% CI 72-112) mm Hg at a postconceptional age of 44-48 weeks irrespective of gestation at birth. CONCLUSION: Systolic blood pressure 4-24 hours after birth was less than gestational age (in weeks) in only 3% of non-disabled long term survivors. Systolic pressure rose with increasing gestation and increasing postnatal age, but stabilised some six weeks after term, regardless of gestation at birth.

Analysis of Variance↗

End-systolic myocardial stiffness is a load-independent index of contractility in stage 24 chick embryonic heart.

Cardiac morphogenesis and function are interrelated during cardiovascular development. We evaluated the effects of acute alteration of loading condition to chick embryonic ventricular contractility using end-systolic myocardial stiffness based on the incremental elastic modulus concept. End-systolic stress-strain relations including geometric factor and end-systolic myocardial stiffness were determined from the simultaneous measurement of ventricular pressure and chamber dimension in the following four groups of stage 24 White Leghorn chick embryos: volume infusion (n = 9), conotruncal occlusion (n = 9), calcium suffusion (n = 10), and verapamil suffusion (n = 8). The end-systolic stress-strain relationship was linear in each embryo. There was no correlation between end-systolic myocardial stiffness and end-systolic stress. End-systolic myocardial stiffness increased with calcium suffusion (P < 0.05 vs. volume infusion). The geometric factor increased after verapamil suffusion (P < 0.05). End-systolic myocardial stiffness normalized by geometric factor was not changed by alteration of preload or afterload, increased after calcium suffusion, and decreased after verapamil administration (P < 0.05). These results suggest that normalized end-systolic myocardial stiffness is a load-independent index of ventricular contractility in the developing embryonic chick ventricle.

Animals↗

The relationship of various measures of end-systole to left ventricular maximum time-varying elastance in man.

This investigation was designed to calculate left ventricular maximum time-varying elastance (Emax), to define the relationship between Emax and pressure-volume (P-V) relations at other, more easily defined measured of end-systole, and to determine whether these measures of left ventricular contractile function can be normalized in man. Accordingly, we studied 10 subjects with simultaneous high-fidelity micromanometer left ventricular and ascending aortic pressure recordings and biplane contrast cineangiograms at control conditions and during infusion of methoxamine and nitroprusside. Emax was defined as the maximum slope of the linear relation of isochronal, instantaneous P-V data points obtained from each of the three loading conditions. Left ventricular end-systole was also defined for each loading condition as: the time of the maximum P-V ratio (maxPV), minimum ventricular volume (minPV), (-)dP/dtmin [(-)dP/dtPV], and zero systolic flow approximated by the central aortic dicrotic notch (AodiPV). The mean heart rates and LV (+)dP/dtmax were insignificantly altered during the three loading conditions. Isochronal Emax ranged from 3.38 to 6.73 mm Hg/ml (mean 5.48 +/- 1.23 [SD] mm Hg/ml) and the volume-axis intercepts at zero pressure ranged from -2 to 51 ml (mean 18 +/- 16 ml). The isochronal slope calculations were reproducible (r = .97 to .99). The end-systolic P-V slope values for the maxPV, minPV, (-)dP/dtPV, and AodiPV relations correlated with isochronal Emax (r = .90, .88, .69, and .74, respectively). The average slope values for these end-systolic P-V relations, however, underestimated the mean Emax (p less than .01 to p less than .001). The mean extrapolated volume-axis intercepts for these end-systolic P-V relations also underestimated that for Emax. Finally, the isochronal Emax and other end-systolic P-V relation slope values demonstrated inverse linear relationships with left ventricular mass (r = -.68 to -.91, p less than .05 to p less than .001). Only the Emax volume-axis intercepts showed a linear relationship with left ventricular end-diastolic volume (r = .75). Thus we conclude that the time-varying elastic properties of the left ventricle can be calculated in man, that commonly used end-systolic P-V relations significantly underestimate isochronal Emax, and that normalization of isochronal Emax and other end-systolic P-V relation slope values might be performed in man with left ventricular mass; no obvious relationship between volume-axis intercepts and measures of left ventricular or body size was apparent.

Adult↗

Timing and velocity of ejection as major determinants of end-systolic pressure in isolated rabbit hearts.

BACKGROUND: Systolic shortening is known to produce muscle deactivation. The present study was designed to analyze whether the velocity and the timing of ejection play a role on end-systolic pressure-volume relations (ESPVR). METHODS AND RESULTS: In isolated rabbit hearts, left ventricular pressure and volume were recorded and digitized, and left ventricular volume was controlled by a servosystem (4-millisecond cycles) to alter the timing of ejection. A significant deficit in end-systolic pressure was observed when ejection was late in systole with respect to earlier ejection. This was associated with a significantly reduced end-systolic elastance. End-systolic pressure of beats with slow ejection was intermediate between that of the beats with early ejection and that of beats with late ejection with a significantly increased end-systolic volume compared with beats with early rapid ejection. The same results were obtained with hypertrophied hearts (abdominal aortic stenosis). Pressure-volume loop areas were significantly increased in beats with slow ejections and with rapid delayed ejections versus early rapid ejections. No change in the positive peak of dP/dt was observed when the timing and the velocity of ejection were modified. CONCLUSIONS: ESPVR is modified by the ejection profile, with a decreased end-systolic pressure and an increased pressure-volume loop area related to the velocity and the amount of shortening during the end-systolic phase. These indices of ventricular function thus must be used with caution when the timing of ejection is altered, and the end-diastolic volume-peak dP/dt relation may be a better index of ventricular function.

Animals↗

Differential control of systolic and diastolic blood pressure : factors associated with lack of blood pressure control in the community.

Data from the Third National Health and Nutrition Examination Survey, phase 2 (1991 to 1994), indicate that among hypertensive individuals in the United States, 53.6% are treated and only 27.4% are controlled to goal levels. We sought to determine whether poor hypertension control is due to lack of systolic or diastolic blood pressure control, or both. We studied Framingham Heart Study participants examined between 1990 and 1995 and determined rates of control to systolic goal (<140 mm Hg), diastolic goal (<90 mm Hg), or both (systolic <140 and diastolic <90 mm Hg). Of 1959 hypertensive subjects (mean age 66 years, 54% women), 32.7% were controlled to systolic goal, 82.9% were controlled to diastolic goal, and only 29.0% were controlled to both. Among the 1189 subjects who were receiving antihypertensive therapy (60.7% of all hypertensive subjects), 49.0% were controlled to systolic goal, 89.7% were controlled to diastolic goal, and only 47.8% were controlled to both. Thus, poor systolic blood pressure control was overwhelmingly responsible for poor rates of overall control to goal. Covariates associated with lack of systolic control in treated subjects included older age (OR for age 61 to 75 years, 2.43, 95% CI 1.79 to 3.29; OR for age >75 years, 4.34, 95% CI 3.10 to 6.09), left ventricular hypertrophy (OR 1.63, 95% CI 1.04 to 2.54), and obesity (OR for body mass index >/=30 versus <25 kg/m(2), 1.49, 95% CI 1.08 to 2.06). In this community-based sample of middle-aged and older subjects, overall rates of hypertension control were remarkably similar to those in the Third National Health and Nutrition Examination Survey. Poor blood pressure control was overwhelmingly due to lack of systolic control, even among treated subjects. Therefore, clinicians and policymakers should place greater emphasis on the achievement of goal systolic levels in all hypertensive patients, especially those who are older or obese or have target organ damage.

Aged↗

Predominance of isolated systolic hypertension among middle-aged and elderly US hypertensives: analysis based on National Health and Nutrition Examination Survey (NHANES) III.

The purpose of the present study was to examine patterns of systolic and diastolic hypertension by age in the nationally representative National Health and Nutrition Examination Survey (NHANES) III and to determine when treatment and control efforts should be recommended. Percentage distribution of 3 blood pressure subtypes (isolated systolic hypertension, combined systolic/diastolic hypertension, and isolated diastolic hypertension) was categorized for uncontrolled hypertension (untreated and inadequately treated) in 2 age groups (ages <50 and >/=50 years). Overall, isolated systolic hypertension was the most frequent subtype of uncontrolled hypertension (65%). Most subjects with hypertension (74%) were >/=50 years of age, and of this untreated older group, nearly all (94%) were accurately staged by systolic blood pressure alone, in contrast to subjects in the untreated younger group, who were best staged by diastolic blood pressure. Furthermore, most subjects (80%) in the older untreated and the inadequately treated groups had isolated systolic hypertension and required a greater reduction in systolic blood pressure than in the younger groups (-13.3 and -16.5 mm Hg versus -6.8 and -6.1 mm Hg, respectively; P:=0.0001) to attain a systolic blood pressure treatment goal of <140 mm Hg. Contrary to previous perceptions, isolated systolic hypertension was the majority subtype of uncontrolled hypertension in subjects of ages 50 to 59 years, comprised 87% frequency for subjects in the sixth decade of life, and required greater reduction in systolic blood pressure in these subjects to reach treatment goal compared with subjects in the younger group. Better awareness of this middle-aged and older high-risk group and more aggressive antihypertensive therapy are necessary to address this treatment gap.

Age Factors↗

Human left ventricular end-systolic pressure-volume relationship in a cylinder model.

The relationship between myocardial total force and length at the end of systole appears to be linear, and the slope of this relationship is considered to be an appropriate index of myocardial contractile state, independent of preload and afterload. However, direct measurements of this relation may be impossible in the intact human heart, and thus, alternative indices such as the left ventricular end-systolic stress-length, stress-strain, pressure-volume, and pressure-dimension slopes have been proposed to evaluate myocardial contractility in the intact heart. However, the mathematical relationship between the myocardial end-systolic total force-length relation and any of these left ventricular end-systolic relations remains unclear. In this study, assuming a linear myocardial end-systolic total force-length relation in an intact ventricle, we obtained mathematical formulae for the left ventricular end-systolic stress-strain, pressure-radius, and pressure-volume relations, using a cylinder model of the left ventricle. The results obtained using these formulae and the cylinder model were found to match accurately findings obtained from earlier experimental and clinical studies of these left ventricular end-systolic relations. Thus, this model could mathematically account for the relationships between the slopes of the myocardial end-systolic total force-length relation and these left ventricular end-systolic relations.

Blood Pressure↗

Effect of pericardium on regional myocardial systolic function in acute ischemia.

To know whether or not the pericardium affects regional myocardial systolic function in acute ischemia, we measured ischemic and non-ischemic segment lengths of the left ventricle using ultrasonic crystals in 10 open-chest dogs with the pericardium preserved. When the left ventricular pressure and segment lengths were stable after left circumflex coronary occlusion, we opened the pericardium widely. After coronary occlusion, end-diastolic length (EDL) in ischemic and non-ischemic segments increased, and the ischemic segment showed paradoxical systolic expansion while the non-ischemic segment increased its active shortening. After pericardiectomy, heart rate, left ventricular systolic pressure, and peak positive and negative dP/dt did not change. EDL in ischemic and non-ischemic segments further increased from 12.02 +/- 0.18 to 12.50 +/- 0.16 mm (mean +/- S.E., p less than 0.01) and from 11.12 +/- 0.20 to 11.45 +/- 0.18 mm (p less than 0.05), respectively, despite the concomitant fall in left ventricular end-diastolic pressure (LVEDP) from 12.4 +/- 0.6 to 10.6 +/- 0.8 mmHg (p less than 0.01). End-systolic length in ischemic and non-ischemic segments also increased from 12.37 +/- 0.25 to 12.70 +/- 0.20 mm (p less than 0.05) and from 8.50 +/- 0.13 to 8.74 +/- 0.13 mm (p less than 0.01), respectively, although the left ventricular end-systolic pressure did not change. Maximum expanded systolic length of the ischemic segment also increased from 12.99 +/- 0.20 to 13.42 +/- 0.16 mm (p less than 0.01). These results indicate that, in acute ischemia, the pericardium inhibits paradoxical systolic expansion of the ischemic region and increase in end-systolic length of non-ischemic segment. Thus, it is concluded that the pericardium modifies the regional myocardial systolic function in acute ischemia, perhaps through the mechanical restraint of the pericardium.

Animals↗

Effects of left ventricular systolic dysfunction on left atrial appendage and left atrial functions in patients with chronic nonvalvular atrial fibrillation.

OBJECTIVE: It has been claimed that left ventricular (LV) systolic dysfunction impairs left atrial (LA) and left atrial appendage (LAA) functions. In this study, we compared the LA and LAA function parameters in patients with chronic nonvalvular atrial fibrillation (AF) with and without LV systolic dysfunction. METHODS AND RESULTS: The study population consisted of 28 patients with chronic nonvalvularAF. Group I consisted of 12 patients with LV systolic dysfunction (mean age: 61 +/- 14 years; LV ejection fraction: 44 +/- 6%), group II of 16 patients with normal LV systolic function (mean age: 52 +/- 15 years; LV ejection fraction: 65 +/- 3%). LV ejection fraction (EF) was measured by echocardiography utilizing bi-plane area length method. The following LA and LAA transoesophageal echocardiography parameters were obtained: I) LA diameter, 2) LAA ejection velocity, 3) LAA filling velocity, 4) LAA ejection fraction, 5) pulmonary venous (PV) systolic velocity, 6) PV diastolic velocity, 7) PV systolic velocity/diastolic velocity ratio. The left atrium diameter was significantly larger in group I than in group 11 (4.7 +/- 0.7 cm vs. 3.8 +/- 0.6 cm, p < 0.05). The LAA ejection velocity and LAA ejection fraction were significantly lower in group I than in group 11 (22.6 +/- 15.5 cm/s vs 37.5 +/- 11.3 cm/s and 26.9 +/- 20.8% vs. 41.3 +/- 10.9%, p < 0.05 for both comparisons). The PV systolic velocity and PV systolic velocity/diastolic velocity ratio were significantly smaller in group I than in group II (26.2 +/- 14.8 cm/s vs. 51.5 +/- 22 cm/s and 0.7 +/- 0.6 vs. 1.2 +/- 0.5, p < 0.05 for both comparisons). Although decreased LAA filling and PV diastolic velocities were determined in group I, no significant difference existed between groups I and II. Thrombus and/or spontaneous echo contrast (SEC) in the LA and/or LAA were more frequent in group I (75% vs. 18%, p < 0.05). CONCLUSION: These results indicate that LV systolic dysfunction impairs various LA and LA function parameters and is associated with an increased frequency of SEC and/or LA thrombus in patients with chronic nonvalvularAF.

Adult↗

Assessment of systolic function by atrioventricular plane displacement in patients with diastolic dysfunction.

OBJECTIVES: Early recognition and appropriate therapy of diastolic dysfunction (DD) is advisable to prevent further progression to diastolic or systolic heart failure and death. The mitral atrioventricular plane displacement (AVPD) method has been shown to be a reliable and simple technique to study left ventricular systolic function in patients, because the mitral annulus can be visualized in almost all patients even if the endocardial borders are difficult to trace. The aim of our study is to estimate the left ventricular ejection fraction by AVPD method (EFAVPD), in addition to Teicholz's short axis method (EF-T) and Simpson's biplane method (EF-2D) in patients with DD. MATERIAL AND METHODS: One hundred and two subjects were submitted to complete echocardiographic assessment, and DD was shown in 62 patients. The systolic mitral AVPD was recorded at 4 sites (septal, lateral, anterior, and posterior) using M-mode and left ventricular ejection fraction was calculated from the AVPD-mean in 62 patients with DD (mean age 55.67 +/- 5.65, 24 men and 38 women) and in 40 age-matched control subjects (mean age 54.07 +/- 6.96, 15 men and 25 women). There were no statistically significant group differences related to age, gender, heart rate or body mass index. However, in the patients with DD, presence of hypertension and/or diabetes mellitus was significantly higher than control subjects. RESULTS: The systolic functions, as assessed by conventional measures in patients with DD and healthy subjects were not stastically different, and were within normal limits. The septal, anterior, lateral and posterior part of the atrioventricular plane values and AVPD-mean during systole were statistically lower in the DD group (12.35 +/- 1.42 mm) compared with controls (15.32 +/- 1.38 mm) (p < 0.001). EFAVPD in patients with DD was statistically lower (62.97 +/- 7.85%) than healthy subjects (79.30 +/- 7.60%) (p < 0.001). Significant positive correlations between EFAVPD and EF-2D (r = 0.325, p < 0.01) and EF-T (r = 0.355, p < 0.01) and FS (r = 0.314, p < 0.01) were found. EFAVPD correlated only with velocity of mitral flow propagation (VPR) in diastolic function parameters (r = 0.374, p < 0.01). CONCLUSIONS: The AVPD method may indicate a systolic dysfunction with a relatively lower AVPD-mean and relatively lower EFAVPD in the DD group compared with controls. This indicated the presence of a statistically significant and mildly reduced left ventricular systolic function by the AVPD method in patients with DD. It might be suggested that DD might be combined with systolic dysfunction. However, isolated diastolic dysfunction is uncommon. The mitral AVPD is reproducible, widely applicable and a simple non-invasive method for the estimation of left ventricular systolic function in patients with DD.

Blood Flow Velocity↗

Improved outcomes with antihypertensive medication in the elderly with isolated systolic hypertension.

Isolated systolic hypertension affects over 15% of all individuals aged >60 years. In the elderly, systolic hypertension is a major modifiable cardiovascular risk factor. Systolic blood pressure (SBP) is associated with higher risk of an adverse outcome, whereas diastolic blood pressure (DBP) is inversely correlated with total mortality, independent of SBP, highlighting the role of pulse pressure as a risk factor. Three placebo-controlled outcome trials on antihypertensive drug treatment in older patients with isolated systolic hypertension have been published: the Systolic Hypertension in the Elderly Program (SHEP), the Systolic Hypertension in Europe (Syst-Eur) Trial and the Systolic Hypertension in China (Syst-China) Trial. These 3 trials demonstrated the benefit of antihypertensive drug treatment. A meta-analysis was performed by pooling the patients from these 3 trials with a subset of patients with isolated systolic hypertension from 5 other trials in the elderly. The pooled results of 15,693 older patients with isolated systolic hypertension prove that antihypertensive drug treatment isjustified if on repeated clinic measurements SBP is 160 mm Hg or higher.

Aged↗

Comparison of repeated measurement of ambulatory and clinic blood pressure readings in isolated systolic hypertension.

Repeated clinic blood pressure measurement was compared with non-invasive ambulatory blood pressure monitoring in 10 elderly subjects with persistent isolated systolic hypertension and 11 normotensive controls. Mean clinic blood pressures +/- Standard Deviation (SD), at visit 1 were 165/81 +/- 12/7 mmHg and 136/87 +/- 14/10 mmHg respectively. Subjects were assessed on three subsequent occasions at weekly intervals. None were receiving antihypertensive or vasoactive medication. Clinical systolic and diastolic blood pressures were consistently higher than the corresponding mean daytime ambulatory blood pressures in both clinical groups at each of the visits. The difference was greater between the systolic pressures than between the diastolic pressures and these differences in systolic pressures were greater in the isolated systolic hypertensives (26 +/- 5 mmHg) than in the normotensives (7 +/- 18 mmHg). Daytime ambulatory readings aggregated from all four visits were normally distributed for both blood pressure components in both clinical groups. In the isolated systolic hypertension group the clinic systolic and diastolic blood pressure measurements corresponded to the 93rd and 85th percentiles of the ambulatory pressures respectively whereas in the normotensives the equivalent percentiles were 69 and 78. These results suggest a pressor response may largely account for the elevated systolic blood pressure seen in elderly subjects with sustained isolated systolic hypertension based on clinic readings.

Aged↗

[Assessment of the prevalence of atherosclerotic lower limb arteriopathy in France as a systolic index in a vascular risk population].

OBJECTIVE: Obliterative arteriopathy of the lower limbs is a severe disease. History taking often underestimates prevalence. In studies using the Rose questionnaire and examining the prevalence of symptomatic arteriopathy defined by the presence of intermittent claudication, prevalence has been rather constant, around 2% in the general population in industrialized countries. A more clinical approach searching for physical anomalies (absence of distal pulse) generally gives higher rates. The most recent data led us to conduct a study focusing on screening for arterial disease using the systolic index (the systolic index is the ratio between the ankle and humeral systolic pressure). A systolic index below 0.90 would be a sign of defective perfusion, increasing in severity with poorly compensated arterial lesions. METHOD: A survey was performed in a random sample of 150 practitioners using an allocation procedure to the nearest colleague in case of refusal. A data sheet containing demographic data and the main risk factors was established for each consulting patient aged from 40 to 80 years. The systolic index was measured in each patient with at least one vascular risk or who consulted for pain in the lower limbs. A simple sequential non-randomized patient recruitment scheme was used. RESULTS: The survey population included nearly 9,000 patients (8,987), 46% men and 54% women, mean age 64 years (table I). Patient risk factors including smoking, diabetes, hypertension, and physical exercise were adjusted for sex and age (table II-VI, IX). The systolic index was recorded in 41% of the population who had a vascular risk factor. Among these patients, nearly one-fourth had a systolic index under 0.90, giving a prevalence in the sample population of 11% (table VII). This rate was also assessed by age and sex (table VIII). Logistic regression evidenced a prognostic value (fig. 1) for smoking, hypertension and sedentary activity, and to a lesser extent, for age and sex. There was a significant difference by latitude, patients living in northern France having a higher risk than those living in southern France (table X). In addition, there was a relationship between the systolic index and spontaneous complaint, showing that this complaint is poorly specific for arterial disease (table XI, XII). CONCLUSION: This epidemiological approach to arteriopathy implemented by general practitioners searching for patients with a vascular profile and measuring systolic index is a novel method. It gave an estimation of prevalence at 11% in the French population, a rate compatible with that reported by other international teams. The method also allowed an analysis of factors affecting the rate.

Adult↗

[Postoperative changes in left ventricular systolic function in patients with aortic valve stenosis].

Left ventricular systolic function in aortic stenosis remains intact for long period due to myocardial hypertrophy. Aim of this study was postoperative follow-up of the left ventricular systolic function both in patients with preserved and with decreased systolic performance. The study comprised 78 patients with severe and moderate aortic valve stenosis, out of whom 42 patients underwent surgery. In the majority of patients (88.1%) systolic function was improved, both in patients with preoperatively preserved systolic performance, and those who were with decreased systolic performance before the surgery. Systolic function was not improved in only 4.8%, while 3 (7.1%) patients died. Systolic function was improved mainly in the patients in whom systolic function disturbance was caused by the increase of afterload, and less frequently in patients with the decrease in myocardial contractility.

Adolescent↗

[Prevalence of isolated systolic hypertension in Chinese adult population].

OBJECTIVE: To evaluate prevalence of isolated systolic hypertension and other subtypes of hypertension, as well as their distribution in Chinese adults. METHODS: A cross-sectional survey was conducted in the mainland China during 2000-2001 with a multistage cluster sampling to select a nationally representative sample of 15,540 Chinese adults aged 35-74, by InterASIA project. Hypertension subtypes were defined among individuals not receiving antihypertensive therapy as follows: isolated systolic hypertension as a systolic blood pressure > or = 140 mm Hg and a diastolic blood pressure < 90 mm Hg, isolated diastolic hypertension as a systolic pressure < 140 mm Hg and a diastolic pressure > or = 90 mm Hg, and combined systolic/diastolic hypertension as a systolic pressure > or = 140 mm Hg and a diastolic pressure > or = 90 mm Hg. Blood pressure for each subject was measured for three readings at sitting position after rest for at least five minutes and an average reading was recorded. A standardized structured questionnaire was used to collect history of hypertension and antihypertensive treatment. RESULTS: Overall, 7.6% (1,181 cases) of adults had isolated systolic hypertension, 7.4% (1,150 cases) combined systolic/diastolic hypertension and 4.4% (683 cases) isolated diastolic hypertension in the sample of 15,540 adults at age 35-74. Prevalence of systolic hypertension increased with age, and was more common in the older women than in the older men. There was no significant difference in prevalence of isolated systolic hypertension between north and south China, but, rural residents had a higher prevalence than urban residents. CONCLUSION: There existed a higher prevalence of systolic hypertension in China, to which enough attention should be paid.

Adult↗