Abstract-Isolated systolic hypertension is a common condition in individuals aged older than 60 years. However, isolated systolic hypertension has also been described in young individuals, although the mechanisms are poorly understood. We hypothesized that in young adults, isolated systolic hypertension and essential hypertension have different hemodynamic mechanisms and the aim of this study was to test this hypothesis in a cohort of subjects from The ENIGMA Study. Peripheral and central blood pressure, aortic pulse wave velocity, cardiac output, stroke volume, and peripheral vascular resistance were determined in 1008 subjects, aged 17 to 27 years. Compared with normotensive subjects, those with isolated systolic hypertension had significantly higher peripheral, central, and mean blood pressure, aortic pulse wave velocity, cardiac output, and stroke volume (PϽ0.001 for all comparisons). However, there were no differences in pulse pressure amplification, heart rate, or peripheral vascular resistance between the two groups. Compared with subjects with essential hypertension, mean pressure, heart rate, and peripheral vascular resistance were all significantly lower in isolated systolic hypertensive subjects, but pulse pressure amplification, aortic pulse wave velocity, cardiac output, and stroke volume were higher (PϽ0.001 for all comparisons). We have demonstrated that in young adults, isolated systolic hypertension and essential hypertension arise from different hemodynamic mechanisms. Isolated systolic hypertension appears to result from an increased stroke volume and/or aortic stiffness, whereas the major hemodynamic abnormality underlying essential hypertension is an increased peripheral vascular resistance. Long-term follow-up of these individuals is now required to determine whether they are at increased risk compared with age-matched normotensive individuals. Key Words: arterial stiffness Ⅲ hemodynamics Ⅲ isolated systolic hypertension Ⅲ stroke volume Ⅲ young adults H ypertension is a common disorder, affecting Ϸ25% of the overall population 1,2 and is a major risk factor for cardiovascular disease. Epidemiological data 2,3 not only show an age-related change in the incidence of hypertension but also in its form. In those aged younger than 50, the predominant form of hypertension is essential hypertension (EH), involving elevation of systolic (SBP) and diastolic pressure (DBP), or DBP alone, which is characterized by increased peripheral vascular resistance (PVR). However, in older individuals, the most common form of hypertension is isolated systolic hypertension (ISH). This affects Ϸ50% of those aged older than 60 4 and, in contrast to EH, is thought to be caused mainly by large artery stiffening, resulting from disruption and fatigue-fracture of elastic fibers. Therefore, ISH is often considered to be an exaggeration of "normal" age-related stiffening seen in most populations. Indeed, we 5 and others 6 have shown that aortic pulse wave velocity (PWV), a measure of arterial stiffness, is increased in pa...

Nonesterified fatty acid concentrations are elevated in obese children, primarily as a result of increases in myristate, palmitate, and oleate. Independent effects of nonesterified fatty acids on circulating adiponectin levels and lipid parameters were observed, although we found no relationship between nonesterified fatty acid concentrations and the insulin resistance identified with obesity.

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Our data show that short-duration, high-intensity cycle ergometer exercise tests can induce significant plasma volume decreases in untrained subjects, which may affect the interpretation of bloodborne biochemical parameters.

In AS there are alterations in the shape of the central arterial pressure waveform associated with augmented aortic systolic pressure and indicative of increased wave reflection. Unfavourable central arterial haemodynamics in AS may contribute to the development of cardiomyopathy but other aetiological factors are probably involved.