An adequate supply of blood to maintain normal respiration of the cardiac musculature is the first requirement for a functionally normal heart. The ability of the heart to increase its work output in exercise and under other circumstances depends first and foremost on the capacity of the coronary system to supply blood to the heart muscle.
Only the strictly coronary types of heart failure are due to inadequate coronary flow as a first cause, but, as will be more apparent later, in all forms of progressive failure the restrictions in the total possible coronary flow limit the work capacity and therefore the life of the heart and in the last instance of the patient. So long as the oxygen supply to the heart can increase with its needs, that organ can continue to function, barring ventricular fibrillation, although it may function very inefficiently and waste a large share of its
M. B. VISSCHER. THE RESTRICTION OF THE CORONARY FLOW AS A GENERAL FACTOR IN HEART FAILURECHAIRMAN'S ADDRESS. JAMA. 1939;113(11):987–990. doi:10.1001/jama.1939.02800360001001