Alterations in Orthostatic Tolerance after Myocardial Infarction and in Congestive Heart Failure¹

Mechanisms governing the postural response and baroreceptor abnormalities in chronic congestive heart failure: effects of acute and long-term converting-enzyme inhibition.

“…14 Orthostatic hypotension does not occur because reflex increase of systemic resistance and heart rate compensate for the peripheral pooling. Activation of the renin-angiotensin system and compensatory change of sympathetic and parasympathetic tone are also important adjustments.2' 5-8 Abelmann and Fareeduddin9' 10 demonstrated that the hemodynamic response to tilt in chronic congestive heart failure is atypical; that is, there was no significant peripheral pooling in the upright posture. Hence, reflex stimulation of increased systemic vascular resistance and heart rate did not appear necessary to avert orthostatic hypotension.…”

“…Studies in animal models and in humans have demonstrated abnormalities of sympathetic and parasympathetic control of heart rate in chronic congestive heart failure. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Few data are available regarding the effects of vasodilator therapy on these abnorrnalities, although this mode of therapy is widely used. '6 Vasodilator therapy could significantly alter the vasoconstriction, volume alterations and hormonal response that normally accompany the assumption of upright posture.…”