CVS

Question 1

What factors determine myocardial oxygen supply?

Give examples of pathology that could affect each factor.

Answer 1

Oxygen carrying capacity of the blood e.g. Hb and and coronary blood flow - Affected by anaemia.

Coronary blood flow is determined by diastolic blood pressure and coronary artery resistance - Diastolic blood pressure - affected by hypotension
Coronary artery resistance - affected by narrowing of arterial wall

Question 2

What factors determine myocardial oxygen demand?

Answer 2

Heart rate - affected by tachycardias

Contractility - affected by thyrotoxicosis (-> HF)

Wall tension - affected by things that result in LVH - hypertension/aortic stenosis