Scientists calculate the energy demands of a beating heart

A 3-D image of a human heart.

In a paper published in Science, researchers compare heart failure, when the heart stops pumping blood throughout the body, to an engine running out of gas. Equipping a car with a blinking light when fuel levels are low helps drivers prevent a mechanical shut-down. As a way to similarly preempt heart failure, scientists profiled how the heart uses energy.

The researchers analyzed 277 metabolic compounds from 110 adults undergoing procedures for
atrial fibrillation, a condition that results in the heart beating faster than normal. One in five patients, 23, had previous signs of heart failure. Nutrient intake and output from the legs of participants were used to compare the heart’s energy demands to other parts of the body.

Under normal conditions, the participants’ hearts relied on a higher proportion of fatty acids for fuel compared to their legs. The heart also excreted amino acids, the breakdown of protein, at a volume 10 times greater than the legs. In heart failure, hearts were twice as likely to use ketones, fat stores used for energy, and released a higher proportion of amino acids. The heart’s reliance on fat and protein instead of carbohydrates as prime energy sources surprised the researchers. However, these differences may be due to fasting or anesthesia used for the medical procedure.

Future research will expand on these novel findings. Translational applications from studying metabolic processes within the heart may also support treatment for heart failure, the leading cause of death worldwide.  

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