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Vasculature of the Heart
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Home / The Thorax / Organs of the Thorax / The Heart
/ Vasculature of the Heart
based on 191 ratings
Original Author(s): Sophie Stanley
Last updated: July 22, 2021
Revisions: 2
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Contents
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Recommended reading
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The entire body must be supplied with nutrients and oxygen via
the circulatory system and the heart is no exception. The coronary
circulation refers to the vessels that supply and drain the heart. Coronary
arteries are named as such due to the way they encircle the heart, much
like a crown.
This article will outline the naming, distribution, and clinical relevance of
vessels in the coronary circulation.
Origin of great cardiac vein and coronary
sinus drainage within the left ventricle
Naming
DL Roberts et al., American Journal of
Physiology -- Legacy Content, 1976
Coronary Arteries
There are two main coronary arteries which branch to supply the entire
heart. They are named the left and right coronary arteries, and arise from
the left and right aortic sinuses within the aorta.
The aortic sinuses are small openings found within the aorta behind the
left and right flaps of the aortic valve. When the heart is relaxed, the
back-flow of blood fills these valve pockets, therefore allowing blood to
enter the coronary arteries.
The left coronary artery (LCA) initially branches to yield the left anterior
descending (LAD), also called the anterior interventricular artery. The
LCA also gives o! the left marginal artery (LMA) and the left circumflex
artery (Cx). In ~20-25% of individuals, the left circumflex artery
contributes to the posterior interventricular artery (PIv).
Acute Coronary Syndrome With STSegment Elevation in Inferior Leads: Is It
Always Right?
Anish Kapil et al., JAMA Internal Medicine,
2021
Intravascular and intracardiac blood
temperatures in man
Skoda Afonso et al., Journal of Applied
Physiology, 1962
Cardiac Type of Partial Anomalous
Pulmonary Venous Connection
Rengarajan Rajagopal et al., Radiology:
Cardiothoracic Imaging, 2020
The right coronary artery (RCA) branches to form the right marginal
artery (RMA) anteriorly. In 80-85% of individuals, it also branches into the
posterior interventricular artery (PIv) posteriorly.
Fig 1 – Anterior view of the arterial supply to the heart.
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Fig 2 – Overview of the branching structure of the coronary arteries.
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Cardiac Veins
The venous drainage of the heart is mostly through the coronary sinus –
a large venous structure located on the posterior aspect of the heart. The
cardiac veins drain into the coronary sinus, which in turn, empties into
the right atrium. There are also smaller cardiac veins which pass directly
into the right atrium.
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The main tributaries of the coronary sinus are:
Great cardiac vein (anterior interventricular vein) – the largest
tributary of the coronary sinus. It originates at the apex of the heart and
ascends in the anterior interventricular groove. It then curves to the left
and continues onto the posterior surface of the heart. Here, it gradually
enlarges to form the coronary sinus.
Small cardiac vein – located on the anterior surface of the heart, in a
groove between the right atrium and right ventricle. It travels within this
groove onto the posterior surface of the heart, where it empties into the
coronary sinus.
Middle cardiac vein (posterior interventricular vein) – begins at the
apex of the heart and ascends in the posterior interventricular groove
to empty into the coronary sinus.
Posterior cardiac vein – located on the posterior surface of the left
ventricle. It lies to the left of the middle cardiac vein and empties into
the coronary sinus.
Fig 3 – Anterior view of the venous drainage of the heart. Supplied by the great and small cardiac
veins
Fig 4 – Posterior view of the heart, showing the venous drainage.
Distribution of the Coronary
Arteries
In general, the area of the heart which an artery passes over will be the
area that it perfuses. The following describes the anatomical course of
the coronary arteries. See Appendix A for a tabular overview of the
arterial distribution.
The RCA passes to the right of the pulmonary trunk and runs along the
coronary sulcus before branching. The right marginal artery arises from
the RCA and moves along the right and inferior border of the heart
towards the apex. The RCA continues to the posterior surface of the
heart, still running along the coronary sulcus. The posterior
interventricular artery then arises from the RCA and follows the posterior
interventricular groove towards the apex of the heart.
The LCA passes between the left side of the pulmonary trunk and the left
auricle. The LCA divides into the anterior interventricular branch and the
circumflex branch. The anterior interventricular branch (LAD) follows the
anterior interventricular groove towards the apex of the heart where it
continues on the posterior surface to anastomose with the posterior
interventricular branch. The circumflex branch follows the coronary
sulcus to the left border and onto the posterior surface of the heart. This
gives rise to the left marginal branch which follows the left border of the
heart.
Fig 4 – Anterior view of territorial arterial supply to the heart.
Fig 5 – Posterior view of territorial arterial supply to the heart.
+
Clinical Relevance: Coronary
Artery Disease
Coronary artery disease or coronary heart disease (CHD) is a
leading cause of death, both in the UK and worldwide. It
describes a reduction in blood flow to the myocardium and
has several causes and consequences.
CHD can result in reduced blood flow to the heart as a result
of narrowing or blockage of the coronary arteries. This may be
due to atherosclerosis, thrombosis, high blood pressure,
diabetes or smoking. All these factors lead to a reduced flow
of blood to the heart through physical obstruction or changes
in the vessel wall.
Angina pectoris is one consequence of CHD. Angina
pectoris describes the transient pain a person may feel on
exercise as a result of lack of oxygen supplied to the heart.
This pain is felt across the chest but is quickly resolved upon
rest. Exercise is a trigger for angina as the coronary arteries fill
during the diastolic period of the cardiac cycle. On exercising,
the diastolic period is shortened meaning that there is less
time for blood flow to overcome a blockage in one of the
coronary vessels in order to supply the heart.
If left untreated, angina can soon progress to more severe
consequences, such as a myocardial infarction. The sudden
occlusion of an artery results in infarction and necrosis of the
myocardium. This means a section of the heart is unable to
beat (which part of the heart depends on which artery has
become occluded). The ECG leads on which an MI change
appears can be used to locate the artery that had been
occluded as shown in the table.
Description
ECG leads with
changes
Artery occluded
Inferior
II, III, aVF
RCA
Anteroapical
V3 and V4
Distal LAD
Anteroseptal
V1 and V2
LAD
Anterolateral
I, aVL, V5 and
V6
Circumflex artery
Extensive anterior
I, aVL, V2-V6
Proximal LCA
True posterior
Tall R in V1
RCA
+
Diagnosis and Treatment of
Coronary Artery Disease
A
Fig 1.6 – A coronary angiogram. Two critical narrowings have been labelled.
blockage in a coronary artery can be rapidly identified by
performing a coronary angiogram. The imaging modality
involves the insertion of a catheter into the aorta via
the femoral artery. A contrast dye is injected into the coronary
arteries and x-ray based imaging is then used to visualise the
coronary arteries and any blockage that may be present.
Immediate treatment of a blockage can be performed by way
of a coronary angioplasty, which involves the inflation of a
balloon within the a!ected artery. The balloon pushes aside
the atherosclerotic plaque and restores the blood flow to the
myocardium. The artery may then be supported by the
addition of an intravascular stent to maintain its volume.
Appendix A – Tabular Overview of
the Vasculature of the Heart
Artery
Vein draining
region
Region supplied
Right atrium
SA and AV nodes
Right coronary
Right marginal
Posterior
interventricular
Small cardiac vein
Middle cardiac vein
Posterior part of
interventricular
septum (IVS)
Right ventricle
Apex
Small cardiac vein
Middle cardiac vein
Right ventricle
Left ventricle
Posterior 1/3 of IVS
Left posterior
ventricular vein
Left atrium
Left ventricle
Left coronary
Great cardiac vein
IVS
AV bundles
Left anterior
descending
Right ventricle
Left ventricle
Great cardiac vein
Anterior 2/3 IVS
Left marginal
Left ventricle
Left marginal vein
Great cardiac vein
Circumflex
Left atrium
Left ventricle
Great cardiac vein
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