Forearm and splanchnic blood flow at rest and during exercise in relation to the systemic arteriovenous oxygen difference in cardiac patients.

In eleven patients with chronic heart failure forearm blood flow (FBF) was measured by plethysmography with a mercury-in-silastic strain gauge and splanchnic blood flow (SBF) with indocyanine green (ICG) infusion clearance at rest during right heart catheterization. The measurements were repeated during 8 min supine exercise on a bicycle ergometer, SBF during exercise being calculated from the changes of the brachial artery to hepatic vein oxygen differences and the ICG values at rest. Close correlations were found between cardiac output and FBF, and cardiac output and SBF at rest. During exercise forearm and splanchnic vascular resistances were both closely correlated with the brachial to pulmonary artery oxygen difference. It is concluded that in patients with heart failure vasoconstriction occurs during exercise in resting limbs and visceral organs, both closely related to the circulatory strain.