cardiovascular shunt left-to-right shunt 2020-09-11T06:55:18Z a left-to-right shunt allows the oxygenated, pulmonary venous blood to return directly to the lungs rather than being pumped to the body thereby reducing the cardiac output by the amount of the shunted volume; as a result, tissue oxygen delivery is reduced left-to-right shunting MP:0031129 L-R shunt MPheno.ontology