Myocardial oxygen demand depends upona) Preloadb) Afterloadc) Intramyocardial tensiond) Blood Hb concentration
There are two terms to remember. Myocardial oxygen demand and myocardial oxygen supply. Hb concentration is a factor for oxygen supply.
Oxygen demand depends on the work being done. The work done is to pump the blood which is in the ventricles (preload) against the resistance in the aorta (afterload).
So, myocardial oxygen demand depends on

Rate- Directly proportional
Contractility- Directly proportional
Intramyocardial tension- Directly proportional
After load- Directly proportional
Preload- Directly proportional
Wall thickness- Inversely proportional
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