[Distribution of left ventricular output]

This survey focuses on distribution of cardiac output to various organs and on some dynamic changes occurring in cardiac output and its distribution.

Data presented are largely related to work carried out in our research group, where Doppler ultrasonography is widely used for measurement of cardiac output and arterial blood flow. Additional data are drawn from relevant literature, in part compiled through search in the PubMed database.

The difference in blood flow to various organs is emphasised, with e.g. brain and endocrine organs receiving large and stable blood supplies, whereas inactive muscles are sparsely perfused. Attention is drawn to distribution patterns in situations where cardiac output is markedly increased. Such situations are muscular exercise, with a dramatic increase in muscle blood flow, the occurrence of bodily heat surplus, with increased skin blood flow, and the postprandial situation, with augmented blood flow to the gastrointestinal tract. Of particular interest are situations where two or more demands for increased blood supply occur simultaneously, such as muscular exercise in the period just after a meal. Physically trained persons are apparently better than others at maintaining gastrointestinal blood supply during exercise.