Abstract: A monitoring device for cardiac efficiency and cardiac sufficiency derived from pre-ejection and post-ejection potentials, cardiac metabolic rate, and cardiac power receives signals representative of ventricular pressures and sizes, body temperature, age, and sex. Cardiac efficiency is determined as the ratio of the mechanical work of the heart performed in one cardiac cycle which is equal to the difference of pre-ejection potential and post-ejection potential to the highest pre-ejection potential. Metabolic rate is determined as a multiple of the minimum cardiac work necessary to sustain life. Cardiac power is determined as the ratio of cardiac work to the time in which this work is performed. Cardiac efficiency and cardiac power are used to determine myocardial impairment, dysfunctions, sufficiency, and insufficiency.