Cardiac Efficiency

Cardiac Efficiency is the ratio of work done by the heart to the energy expended in performing the work.

Where:

• CE = Cardiac Efficiency
• SW = Stroke Work
• `QO_2` = oxygen consumption

The work done by the heart is usually assessed based on the total work performed by the two ventricles, converted from kilogram-meters into calories. The energy consumption of the heart is determined based on its oxygen consumption, and the ratio of oxygen to energy, called the respiratory quotient, which is essentially the efficiency of the mitochondria in cardiac cells to convert oxygen into usable energy.