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You are watching: The myocardium receives its blood supply from the

StatPearls . Sweetheart Island (FL): StatPearls Publishing; 2021 Jan-.


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Introduction

The coronary arteries carry out the main blood supply to the heart. The coronary arteries additionally supply the myocardium through oxygen to permit for the convulsion of the heart and thus leading to circulation of the blood transparent the body. Two main coronary arteries originate from the base of the aorta together it exit the left ventricle: the left and also right coronary arteries. These arteries more branch into smaller arteries come supply specific parts of the heart prefer the atria, ventricles, SA, and also AV nodes. The is vital to realize the the courses these arteries take might vary slightly from human being to person.


Structure and also Function

The role of the arteries of the love is to carry out oxygen and also nutrients come the myocardium to enable for contraction of the heart, which reasons blood come circulate transparent the body. The arteries of the heart are additionally capable of autoregulation and can regulate the amount of blood circulation supplying the love according to its need. The coronary arteries get the many blood flow during diastole because this is when the heart is relaxed, and they obtained the least blood flow throughout systole due to the fact that this is as soon as the myocardium contracts space decreasing the blood circulation through the coronary arteries.


Blood Supply and Lymphatics

The coronary arteries split into two, key arterial branches native the basic of the aorta. They space the left and right coronary arteries: 

The left coronary artery (LCA) extends along the coronary sulcus and also supplies the left portion of the heart. It further branches into the circumflex artery and the anterior interventricular artery (left anterior descending artery). The anterior interventricular artery more divides right into septal branches and diagonal branches.


The septal branches supply the anterior two-thirds of the interventricular septum and bundle the His.
The diagonal branch supplies the anterolateral papillary muscle and the anterior and lateral parts of the left ventricular wall.
The circumflex artery follows the coronary sulcus to the left part of the heart and further divides into the left marginal artery and also posterior left ventricular artery. The circumflex artery and also its branches supply the posterolateral section left ventricle.

The ideal coronary artery (RCA) traces along the ideal coronary sulcus and also provides blood circulation to the anterior and diaphragmatic surfaces of the ideal atrium and also ventricle; and also the posterior two-thirds of the interventricular septum.


The initial 2 branches that come turn off the RCA are the conus artery which gives blood circulation to the infundibulum of the best ventricle where the pulmonary artery arises and the branch that the SA node which offers blood supply to the SA node.  
As the RCA travels follow me the coronary sulcus, it provides off the appropriate marginal artery i m sorry travels follow me the acute margin (anteroinferior border) the the heart. The best marginal artery is used in angioplasty to differentiate the worse border the the heart, and also it gives blood flow to the best ventricle.
As the RCA travel to the posterior portion of the heart, the posterior interventricular artery (posterior to decrease artery) and also right posterolateral artery at the crux cordis branch off. The crux cordis is offered as a landmark in angiography.
Both the posterior diminish artery (PDA) and also the ideal posterolateral artery space terminal branches. The posterior descending artery (PDA) offers off septal branches the supply the posterior one-third of the interventricular septum. The ideal posterolateral arteries might provide part of the left posterior atrium and also ventricles.
Eventually, in ~ the end of the RCA course, it gives off the branch of the AV node. The branch of the AV node branches turn off at the diaphragmatic surface and also supplies the AV node.

Anastomosis occurs in a few places of the heart also though the coronary arteries are thought about end arteries.


One anastomosis is between the branches that the LAD from the LCA and also the branches of the PDA native the RCA.
Another one is in between the RCA and also the left circumflex artery in the coronary sulcus.
A third anastomosis occurs through the septal branches that both arteries in ~ the interventricular septum.

Coronary Venous Anatomy

Just choose the coronary arteries, there space coronary veins that drain the myocardium the deoxygenated blood. In general, there is twice the number of coronary veins together arteries, and also the circulation occurs throughout both systole and also diastole.

The coronary veins room organized right into two groups: greater and smaller cardiac veins. The better cardiac veins covers the coronary sinus, atrial veins, anterior cardiac veins, and also veins draining the septum. The better cardiac veins account for 95% of all venous drainage from the heart. The smaller sized cardiac veins additionally known together the thebesian veins space luminal vessels and also drain directly into the corresponding cardiac chambers.

All the venous blood indigenous the love arrives at the coronary sinus i beg your pardon is situated in the atrioventricular groove. The coronary sinus is the biggest cardiac vein, and it empties directly into the best atrium in ~ the connect of the coronary and also the interventricular grooves. The coronary sinus does have actually a little valve-like structure.


Nerves

The medulla offers sympathetic and also parasympathetic innervation come the heart and also coronary arteries. The sympathetic innervation is via the cardiac fibers from the superior, middle, and inferior cervical ganglion. Forgiveness innervation reasons vasodilation the the coronary arteries. The parasympathetic innervation is via the vagus nerve. The vagus nerve will constrict the coronary arteries.  


Physiologic Variants

There are numerous anatomic sport in the blood supply of the heart. One of the greatest distinctions is determining even if it is the love is RCA dominant, LCA dominant, or codominant. The prominence of the heart counts on wherein the PDA is obtained from.


If the PDA branch comes off the LCA, the patience is said to it is in LCA dominant; this occurs in around 10% of cases.
The patience may likewise be codominant, definition the PDA is gave by both right and also left coronary arteries, this wake up in 20% of cases. This is significant because if the LCA and obstruction supply the PDA, the LCA have the right to be an ext damaging and critical

Important congenital coronary artery anomalies exist.  Children born through an anomalous left coronary native the pulmonary artery (ALCAPA) current with congestive love failure approximately 4-6 month of age.  An anomalous left coronary artery indigenous the best sinus coursing between the pulmonary artery and also the aorta is associated with sudden death during exercise.<2><3>

Coronary artery an illness is uncommon in young civilization except in rare instances of homozygous familial hypercholesterolemia.<4>


Surgical Considerations

Percutaneous coronary treatment (PCI) space non-surgical measures that space recommended as soon as a patience is diagnosed through unstable angina, non-ST elevated myocardial infarction, or ST-elevated myocardial infarction. The goal of this procedure is to relieve the narrowing or occlusion that the coronary artery. PCI contains procedures such as angiography, angioplasty, and stent placement and should be done within 90 minutes of the patient"s come to the emergency department. These steps are done in the cath rap to assist visualize the obstruction and also revascularize the heart. Angioplasty allows the image of the arteries and localizing the the narrowing the the coronary artery. After narrowing is figured out a balloon angioplasty deserve to be done where a balloon is inflated causing growth of the narrowed artery and improving blood flow. A stent is a mesh pipe that have the right to be put to keep the coronary artery open.<5>


Clinical Significance

A myocardial infarction occurs once there is a narrowing or occlusion of a coronary artery due to atherosclerosis (plaque buildup because of cholesterol). In one infarction blood it is provided is insufficient to the contracting myocardium and also oxygen it is provided does not meet oxygen need causing cell death. This causes an ST-segment key on an ECG due to abnormal conduction through the heart.

Coronary arteries are finish arteries, and this method there is just one resource of blood supply to the myocardium increasing the hazard of endocardial damages due to narrowing.

Considering the the function of the arteries is to it is provided the heart through oxygen, that is important to recognize which artery supplies which portion of castle in bespeak to be able to read an electrocardiogram (EKG). Understanding which leads in an ECG exchange mail to details arteries helps localize the location of the obstruction i beg your pardon can create predictable patterns.<6><7>


A posterior infarction mirrors ST depression in leader V1, V2, V3, and large R wave, and also the vessels involved are proximal RCA and left circumflex.
An anterior infarction mirrors an ST elevation in leads V1, V2, V3, and V4, and also the vessel connected is the LAD.
Lateral infarction shows ST elevation in leads I, AVL, V5, and also V6, and also the vessel consisted of is the left circumflex.
Right ventricular infarction mirrors elevations in leader II, III, and also V1, and also the vessel contained is the proximal RCA.

Other Issues

Anomalous coronary arteries have the right to be a diagnostic challenge. Lock may take place either singly or in mix with other congenital heart disorders. The incidence that anomalous coronary vessels has been report to be around 0.1% to 0.3% in necropsy reports. Although rare, they deserve to often present with hemodynamic abnormalities. Many coronary anomalies are very first identified on one angiogram due to the fact that of their anomalous course.

Type that Coronary Anomalies

High Takeoff: where the origin of the LCA or RCA is over the normal anatomical location. This anomalies may existing with difficulty in cannulation throughout angiography.

Multiple ostia whereby the RCA and also the conus branch may arise separately, or the LAD and also left circumflex may arise with no left usual coronary artery.

Single Coronary Artery: once there is only one coronary artery emerging from the aortic trunk. It might be the RCA or the LAD.  If the solitary coronary passes in between the aorta and pulmonary artery, it have the right to be compressed and present with sudden death.

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Anomalous beginning of the coronary artery from the pulmonary artery is the many serious congenital coronary artery anomaly. Most babies are symptomatic at birth. In the most usual type, the left usual coronary arises from the pulmonary artery through the RCA arising normally. These patients require some procedure to transform it right into a twin coronary artery system. The bypass have the right to be carried out with a saphenous vein graft or interior mammary, but the small size the the coronary is a major limiting factor. Rarely, this can existing in adolescents and adults.<9><2><10>