Coronary perfusion — FRCA Primary MCQ

Correct answer: B — Left ventricular coronary perfusion occurs mainly in diastole

Left ventricular coronary flow is greatest during diastole. Right ventricular afterload rises with pulmonary vascular resistance is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Hypothermia shifts the oxyhaemoglobin curve left is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Aldosterone increases sodium reabsorption and potassium secretion is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Reduced baroreceptor firing increases sympathetic outflow is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. In Primary FRCA physiology, the correct answer is usually the variable that best explains the observed change in the anaesthetised patient.

Reference: West's Respiratory Physiology; Ganong Review of Medical Physiology; Primary FRCA textbooks