Postural differences in hemodynamics and diastolic function in healthy older men

Abstract

The shift from upright to supine posture increases stroke volume in healthy young adults, primarily through increased end-diastolic volume. Aging is associated with increased ventricular stiffness and impaired diastolic function. The purpose of this study was to determine whether the stroke volume change between the upright and supine posture was blunted in healthy older men and whether the early mitral inflow response to this postural change was reduced by aging. Pulsed Doppler echocardiography and tissue Doppler imaging were used to assess stroke volume and left ventricular function during upright and supine posture in 10 young and 12 older healthy men. Cardiac output was greater in the supine versus upright condition in both groups. In young men supine posture was associated with a large increment in stroke volume (63.1 +/- 7.2 upright to 98.6 +/- 11.7 ml supine; P < 0.05) and a decrease in heart rate. In older men, the stroke volume increment was smaller (63.9 +/- 3.6 upright to 82.0 +/- 5.7 ml supine; P < 0.05) and heart rate decreased less than young men when comparing upright to supine posture. Increased stroke volume was associated with higher peak early diastolic filling velocity (E) in young men and higher peak late diastolic filling velocity (A) in older men. These findings indicate that healthy aging attenuates the increase in early filling associated with moving from an upright to a supine posture. Furthermore, healthy older men are more dependent upon atrial diastolic filling to augment end-diastolic and stroke volume, which may be due to age-associated increases in left ventricular filling pressure and impaired compliance.

Exercise with a Twist: Left Ventricular Twist and Recoil in Healthy Young and Middle-Aged Men, and Middle-Aged Endurance-Trained Men

“…MTsubjects demonstrated a trend toward achieving higher end-diastolic volume during exercise, and this may be attributed to the training-induced increase in LV compliance and the consequent ''right-shifted'' pressure-volume relationship. 1,19 These ventricular adaptations influencing improved diastolic function in the athlete's heart are widely accepted, yet there are other ventricular adaptations underpinning the recruitment of twist in these highly trained individuals that require further elucidation.…”

“…Peak E-wave velocity at rest was significantly greater in YU subjects compared to MU and MT subjects, consistent with prior studies of healthy MU men. 19 The higher peak A-wave velocities during exercise for MU subjects suggest that chronic endurance training reduces the age-dependent increase in the atrial contribution to LV filling. The LV pressure-volume relationship in middle-aged individuals is shifted upward and to the left, reflecting a reduction in LV compliance.…”

Reported normal values and weighted means for commonly used echocardiography pulsed Doppler and tissue Doppler measurements

“…Overall, PW over the mitral valve or in the pulmonary vein is more prone to be affected than TDI. The impact of changes in loading conditions on PW and TDI variables has been investigated in several different ways such as after tilt‐test, haemodialysis, active change of posture, nitro‐glycerine application, leg lifting or food intake (Stoddard et al ., ; Downes et al ., ; Voutilainen, ; Møller et al ., ; Barberato et al ., ; Baldi et al ., ; Lee et al ., ; Dencker et al ., ). Most of these changes in loading conditions are irrelevant in clinical practice and to the data in this summary, because you usually know the subjects′ posture or at which elevation they have their legs.…”

What about the other two-thirds of the cardiac cycle?

“…Indeed, this index is not only preload dependent, but also, as healthy patients age and alter their posture, mitral flow velocity profiles deviate from the expected norm. 8,9 These limitations have resulted in the development of a number of other indices of diastolic dysfunction, including tissue velocity imaging and myocardial strain and strain rate imaging. 10 In their elegant paper in this issue of the Journal, Couture et al 11 employed many of these indices in an effort to evaluate whether induction of anesthesia in patients with pre-existing diastolic dysfunction effected a change in myocardial diastolic performance.…”

“…En effet, cet indice dépend non seulement de la précharge; en plus, tandis que des patients sains vieillissent et changent leur posture, les profils de vélocité du flux mitral tendent à dévier de la norme attendue. 8,9 Ces limites ont généré l'élaboration de plusieurs autres indices de dysfonction diastolique, notamment l'imagerie de la vélocité tissulaire et l'imagerie de la déformation myocardique et du taux de déforma-tion. 10 Dans leur article intéressant dans ce numéro du Journal, Couture et coll.…”