Coronary circulation

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Coronary Angiography


General Principles

Historical Perspective
Appropriate Use Criteria for Revascularization
Film Quality

Anatomy & Projection Angles

Normal Anatomy

Coronary arteries
Right System
Left System
Left Main
Left Anterior Descending
Median Ramus

Anatomic Variants

Separate Ostia
Anomalous Origins
Case Example

Projection Angles

Standard Views
Left Coronary Artery
Right Coronary Artery

Epicardial Flow & Myocardial Perfusion

Epicardial Flow

TIMI Frame Count
TIMI Flow Grade
TIMI Grade 0 Flow
TIMI Grade 1 Flow
TIMI Grade 2 Flow
TIMI Grade 3 Flow
TIMI Grade 4 Flow
Pulsatile Flow

Myocardial Perfusion

TIMI Myocardial Perfusion Grade
TMP Grade 0
TMP Grade 0.5
TMP Grade 1
TMP Grade 2
TMP Grade 3

Lesion Complexity

ACC/AHA Lesion-Specific Classification of the Primary Target Stenosis

Preprocedural Lesion Morphology

Intimal Flap
Sawtooth Pattern
Ostial location
Proximal tortuosity
Degenerated SVG
Total occlusion
Coronary Artery Thrombus
TIMI Thrombus Grade
TIMI Thrombus Grade 0
TIMI Thrombus Grade 1
TIMI Thrombus Grade 2
TIMI Thrombus Grade 3
TIMI Thrombus Grade 4
TIMI Thrombus Grade 5
TIMI Thrombus Grade 6

Lesion Morphology

Quantitative Coronary Angiography
Definitions of Preprocedural Lesion Morphology
Irregular Lesion
Disease Extent
Arterial Foreshortening
Infarct Related Artery
Degenerated SVG

Left ventriculography

Quantification of LV Function
Quantification of Mitral Regurgitation

Template:Infobox Anatomy Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Rim Halaby, M.D. [3]


The coronary circulation is the circulation of blood in the blood vessels that supply blood to and from the heart muscle itself. Although blood fills the chambers of the heart, the muscle tissue of the heart, the myocardium, is so thick that it requires coronary blood vessels to deliver blood deep into it. The coronary arteries are the vessels that deliver oxygen-rich blood to the myocardium. Cardiac veins are the vessels that remove the deoxygenated blood from the heart muscle. Epicardial coronary arteries are the coronary arteries that run on the surface of the heart. These arteries, when healthy, are capable of autoregulation to maintain coronary blood flow at levels appropriate to the needs of the heart muscle. These relatively narrow vessels are commonly affected by atherosclerosis and can become blocked, causing angina or a heart attack. Subendocardial coronary arteries run deep within the myocardium. The coronary arteries are classified as end circulation, since they represent the only source of blood supply to the myocardium: there is very little redundant blood supply, which is why blockage of these vessels can be so critical.

Coronary Arteries and Veins

Coronary Arteries

he coronary arteries supply oxygenated blood to the heart muscle itself. Although blood fills the chambers of the heart, the muscle tissue of the heart, or myocardium, is so thick that it requires coronary blood vessels to deliver blood deep into it. There are two primary arteries supplying the heart, the left coronary artery and the right coronary artery. These two epicardial coronary arteries course along the surface of the heart and this is why they are called "epicardial" (on top of the heart) arteries. Smaller arteries dive deep into the heart muscle and are called subendocardial coronary arteries.

Click here for details about coronary arteries.

Cardiac Veins

The cardiac veins are the vessels that remove the deoxygenated blood from the heart muscle and return it to the right atrium.

Click here for details about cardiac veins.

Shown below is an image depicting the coronary arteries and cardiac veins.

Coronary arteries

Blood Supply to the Papillary Muscles

  • The anterolateral papillary muscle:
    • It receives two blood supplies: the LAD and LCX.
    • It is therefore somewhat resistant to coronary ischemia (insufficiency of oxygen-rich blood).
  • The posteromedial papillary muscle:
    • It is supplied only by the PDA.
    • This makes the posteromedial papillary muscle significantly more susceptible to ischemia.
  • The clinical significance of the nature of blood supply to the papillary muscles is that a myocardial infarction involving the PDA is more likely to cause mitral regurgitation.

Coronary flow

  • During contraction of the ventricular myocardium (systole), the subendocardial coronary vessels (the vessels that enter the myocardium) are compressed due to the high intraventricular pressures. However the epicardial coronary vessels (the vessels that run along the outer surface of the heart) remain patent. Because of this, blood flow in the subendocardium stops.
  • As a result most myocardial perfusion occurs during heart relaxation (diastole) when the subendocardial coronary vessels are patent and under low pressure. This contributes to the filling difficulties of the coronary arteries.
  • Failure of oxygen delivery via increases in blood flow to meet the increased oxygen demand of the heart results in tissue ischemia, a condition of oxygen debt.
    • Brief ischemia is associated with intense chest pain, known as angina.
    • Severe ischemia can cause the heart muscle to die of oxygen starvation, called a myocardial infarction.
    • Chronic moderate ischemia causes contraction of the heart to weaken, known as myocardial hibernation.
  • In addition to metabolism, the coronary circulation possesses unique pharmacologic characteristics. Prominent among these is its reactivity to adrenergic stimulation. The majority of vasculature in the body constricts to norepinephrine, a sympathetic neurotransmitter the body uses to increase blood pressure.
    • In the coronary circulation, norepinephrine elicits vasodilation, due to the predominance of beta-adrenergic receptors in the coronary circulation.
    • Agonists of alpha-receptors, such as phenylephrine, elicit very little constriction in the coronary circulation.


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