Final answer:
Afterload is not a determinant of myocardial oxygen supply; it refers to the resistance the heart must overcome to pump blood but does not directly affect the oxygen supply to the heart muscle.
Step-by-step explanation:
The question at hand asks which of the following is NOT a determinant of myocardial oxygen supply: Hemoglobin level, Afterload, Blood oxygen saturation, Coronary blood flow, Diastole time. Understanding the physiology of the heart is key here. The myocardial oxygen supply depends heavily on factors such as Hemoglobin level, Blood oxygen saturation, and Coronary blood flow; these factors ensure that sufficient oxygen is carried to and reaches the heart muscle. Additionally, the Diastole time also plays a role, as it is the period when the heart muscles relax and the coronary vessels fill, thus affecting oxygen delivery.
Afterload, however, is a determinant of the heart's workload and refers to the resistance that the ventricles face while pumping blood out of the heart. While it does have an impact on cardiac function, it is not a direct determinant of the oxygen supply to the myocardium. Therefore, B. Afterload is the correct answer, as it is not a direct determinant of myocardial oxygen supply.