What affects coronary blood flow?

What affects coronary blood flow?

Regulation of coronary blood flow is understood to be dictated through multiple mechanisms including extravascular compressive forces (tissue pressure), coronary perfusion pressure, myogenic, local metabolic, endothelial as well as neural and hormonal influences.

What causes an increase in coronary blood flow?

The increase in flow is mainly determined by simultaneous rises in arterial pressure and heart rate: the contribution of the increase in cardiac output in determining the elevation in coronary flow is less significant (Alella et al., 1955; Marchetti and Merlo, 1964).

What causes decreased coronary blood flow?

The reduced blood flow is usually the result of a partial or complete blockage of your heart’s arteries (coronary arteries). Myocardial ischemia, also called cardiac ischemia, reduces the heart muscle’s ability to pump blood. A sudden, severe blockage of one of the heart’s artery can lead to a heart attack.

Does coronary blood flow increase during systole?

In most tissues, blood flow peaks during ventricular systole due to increased pressure in the aorta and its distal branches. Bloodflow through the coronary vessels, however, is seemingly paradoxical and peaks during ventricular diastole.

How does the diastolic blood pressure affect coronary perfusion?

Evidence exists that subendocardial perfusion occurs during the diastolic period. In the absence of coronary stenosis and myocardial hypertrophy, coronary blood flow increases proportionally as diastolic perfusion time decreases during stress tests.

How does heart rate affect coronary circulation?

Blood flow per single cardiac cycle is reduced at increased heart rate, reflecting the decrease in diastolic duration. From Colin et al. (2004). This is because any increase in heart rate also shortens the duration of diastole and thus creates an impediment to coronary blood flow.

Why is coronary blood flow greatest during diastole?

Coronary blood flow occurs mostly during diastole because the coronary vasculature has one particular property: it is compressed by the contracting myocardium such that no flow occurs during systole.

When does coronary blood flow occur?

Cardiovascular Pharmacology Coronary blood flow occurs mostly during diastole because the coronary vasculature has one particular property: it is compressed by the contracting myocardium such that no flow occurs during systole.

How does blood flow through the coronary circuit?

In the human heart, two coronary arteries arise from the aorta just beyond the semilunar valves; during diastole, the increased aortic pressure above the valves forces blood into the coronary arteries and thence into the musculature of the heart.

What is coronary blood circulation?

Coronary circulation is the circulation of blood in the blood vessels that supply the heart muscle (myocardium). Coronary arteries supply oxygenated blood to the heart muscle. Cardiac veins then drain away the blood after it has been deoxygenated.

When does blood flow into the coronary arteries?

The coronary arteries receive the most blood flow during diastole because this is when the heart is relaxed, and they received the least blood flow during systole because this is when the myocardium contracts are decreasing the blood flow through the coronary arteries.