Cardiac Efficiency

Cardiac efficiency is the proportion of energy used by the heart to the energy used to perform the work. This measurement is analogous to the assessment that might be made of an engine, where the rating is based on the amount of work it is able to do given a certain amount of resources or energy. The energy used  by the heart is usually assessed based on the total work performed by both ventricles, converted from Joules into calories. The metabolic energy consumption of the heart is determined based on its oxygen consumption, and the standard ratio of oxygen to energy consumed by the mitochondria, called the respiratory quotient, which is essentially the efficiency of the mitochondria in cardiac cells to convert oxygen into usable energy [1].

`"Cardiac Efficiency" = "Stroke Work" / (O_2"Consumed"`

Our inputs for this equation are:

• Stroke Work  (Joules)
• Oxygen Consumption (calories)