One of the most unexpected findings in recent years has been the constitutive role of sympathetic activity in the supine hypertension of autonomic failure. Supine hypertension is seen in approximately half of the patients with autonomic failure. The mechanism of supine hypertension in these patients is heterogeneous. In patients with MSA, also termed as Shy-Drager syndrome, blood pressure was uniformly and considerably reduced by ganglionic blockade. This implied that the residual sympathetic activity accounted for most of the hypertension in these subjects. In contrast, ganglionic blockade had little to no effect in patients with pure autonomic failure (PAF). This finding indicates that mechanisms other than sympathetic tone were responsible for hypertension in PAF patients (41).
Differences in sympathetic tone between MSA and PAF patients are also reflected in the power spectrum of blood pressure variability. PAF patients had greatly reduced LFSBP, with no consistent change during trimethaphan infusion. In contrast, LFSBP power was high in patients with MSA, and was greatly reduced by trimethaphan o
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...