Orthostatic hypotension in the elderly: Contributions of impaired LV filling and altered sympathovagal balance

Orthostatic hypotension, which occurs in 5%-18% of the elderly, may contribute to age-related disability. While autonomic dysfunction and alterations of cardiac structure and function likely to impair postural maintenance of blood pressure are common in the elderly, these have not been jointly studied in large cohorts. The authors evaluated the association of orthostatic hypotension with echocardiographic measures of cardiac structure and function, and with autonomic function determined by analysis of heart rate variability, in a large population of community-dwelling elderly. A total of 5201 men and women, aged 65-100 years and living in four geographically separate communities, were recruited from Medicare eligibility lists. In this prospective, observational cohort study, measurements included clinical questionnaires, standing and supine blood pressures, mini-glucose tolerance testing, echocardiography, and 24-hour Holter recording for assessment of heart rate variability. Orthostatic hypotension, defined as a decrease in standing systolic blood pressure of 20 mm Hg or more, was positively associated in bivariate analyses with left ventricular wall thickness, peak velocity of late diastolic filling, vagal tone on heart rate variability analysis, supine systolic pressure, supine diastolic pressure, age, and diabetes, and inversely associated with body weight. After statistical adjustment for the presence of myocardial infarction, stroke, and use of antihypertensive medication, the associations were maintained, and a previous trend toward an association with decreased left ventricular cavity size became statistically significant. The data suggest that in elderly, community-based individuals, orthostatic hypotension is associated with increased blood pressure and decreased weight; it possibly acts mechanistically via altered sympathovagal balance, increased left ventricular wall thickness, decreased left ventricular preload, and alterations of left ventricular diastolic filling.