Myocardial O2 Supply — FRCA Primary MCQ
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Correct answer: E — An increase in arterial oxygen content at unchanged coronary blood flow and demand
The best answer is “An increase in arterial oxygen content at unchanged coronary blood flow and demand”. Myocardial oxygen delivery equals coronary blood flow multiplied by arterial oxygen content. Increasing arterial oxygen content therefore raises delivery if coronary flow is fixed. Heart rate can shorten diastole and increase demand; right-sided and pulmonary pressures are not the direct determinants. Coronary driving pressure, resistance and diastolic time determine the flow component.
Reference: Resuscitation Council UK, Adult Advanced Life Support Guidelines 2025: https://www.resus.org.uk/cy/node/36438