In rat hearts outside the body, butyrate at a certain dose made the heart pump harder, increasing pressure by 14.1%.

In rat hearts, butyrate at a higher dose increased blood flow through the heart's arteries by 20.9%.

In rats, giving butyrate at a certain concentration made the heart pump 48.8% more blood without changing blood pressure or heart rate.

In rats, butyrate made blood vessels wider, reducing resistance by 33.5% without changing blood pressure or heart rate.

When added to isolated rat hearts, a ketone body made the heart muscle contract more strongly and increased blood flow to the heart muscle itself.