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Papillary muscles are thick bands and ridges of endocardial-lined myocardium that project into the lumen of the cardiac ventricles. They are components of the cardiac muscle chambers that play a crucial role in the proper opening and closing of atrioventricular valves. There are five papillary muscles in the heart: three in the right ventricle and two in the left ventricle. Papillary muscle abnormalities can significantly impair the hemodynamic performance of the heart.
| Characteristics | Values |
|---|---|
| Location | Ventricles of the heart |
| Composition | Cardiac muscle tissue and connective tissue |
| Number | Five in total: three in the right ventricle and two in the left ventricle |
| Function | Prevent inversion or prolapse of the atrioventricular valves on systole (or ventricular contraction) |
| Blood supply | Left anterior descending artery, diagonal branch, left circumflex artery, obtuse marginal branch, and right coronary artery |
| Abnormalities | Fibrotic scarring, rupture, congenital malformations, calcification, displacement, and restricted chordae and leaflet motion |
| Clinical aspects | Myocardial infarction, ischemia, blunt chest trauma, mitral regurgitation, ventricular arrhythmias, and ablation techniques |
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What You'll Learn
Papillary muscles are found in the ventricles of the heart
The papillary muscles are thick bands and ridges of endocardial-lined myocardium that project into the lumen of the cardiac ventricles. They are components of the cardiac muscle chambers that play a crucial role in the proper opening and closing of the atrioventricular valves. They are found in both the left and right ventricles of the heart, with three in the right ventricle and two in the left ventricle.
The papillary muscles attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae. They contract to prevent inversion or prolapse of these valves during systole (ventricular contraction). The contraction of the papillary muscles also prevents regurgitation, or the backward flow of ventricular blood into the atrial cavities, by bracing the atrioventricular valves against prolapse.
The papillary muscles originate from the distal third of the ventricular wall in the posteromedial and anterolateral positions, either as a single entity or a group of two to three "papillae". The muscle fibres are mostly oriented longitudinally, resulting in a prevalent shortening of the long axis of the papillary muscles. This shortening is essential to prevent the prolapse of the leaflets, as the length of the chordae tendineae remains the same during the cardiac cycle.
Abnormalities in the papillary muscles, such as fibrotic scarring, rupture, or congenital malformations, can significantly impair the haemodynamic performance of the heart. Rupture of the papillary muscles can be caused by myocardial infarction, and dysfunction can be caused by ischemia or, rarely, blunt chest trauma.
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They contract to prevent the inversion of atrioventricular valves
The papillary muscles are thick bands and ridges of endocardial-lined myocardium that project into the lumen of the cardiac ventricles. They are components of the cardiac muscle chambers that play a crucial role in the proper opening and closing of atrioventricular valves. There are five papillary muscles in the heart: three in the right ventricle and two in the left ventricle.
The papillary muscles attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae. They contract to prevent the inversion or prolapse of these valves during systole (ventricular contraction). The contraction of the papillary muscles maintains the proportions between the valve annulus and the heads of the papillary muscles, preventing valve leaflets from prolapsing. This also prevents regurgitation, or the backward flow of ventricular blood into the atrial cavities, by bracing the atrioventricular valves against prolapse.
The papillary muscles of both the right and left ventricles begin to contract shortly before ventricular systole and maintain tension throughout. The right ventricle's three papillary muscles include the anterior, posterior, and septal papillary muscles. The anterior papillary muscle attaches to the chordae tendineae of the anterior and posterior cusps, the posterior papillary muscle attaches to the chordae tendineae of the posterior and septal cusps, and the septal papillary muscle attaches to the chordae tendineae of the anterior and septal cusps. The left ventricle's two papillary muscles include the anterolateral and posteromedial papillary muscles, which attach to the mitral valve via the chordae tendineae.
Papillary muscle abnormalities can significantly impair the haemodynamic performance of the heart. These abnormalities include fibrotic scarring, rupture, or congenital malformations. Rupture of the left ventricular papillary muscles is a rare complication of myocardial infarction, but it can lead to acute mitral regurgitation, a life-threatening condition. Papillary muscles can also become calcified in advanced Barlow's disease, restricting chordae and leaflet motion.
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They are composed of cardiac muscle tissue and connective tissue
The papillary muscles are thick bands and ridges of endocardial-lined myocardium that project into the lumen of the cardiac ventricles. They are composed of cardiac muscle tissue and connective tissue. The connective tissue serves as the framework for the muscles, organising and separating individual groups of muscle fibres uniformly. The muscle fibres are mostly oriented longitudinally, running parallel to the muscle axis. However, in the peripheral region of the papillary muscles, the muscle fibres are arranged in a circular fashion.
The papillary muscles play a crucial role in the proper opening and closing of the atrioventricular valves. They attach to the cusps of these valves via the chordae tendineae. During systole, the papillary muscles contract to prevent the valves from prolapsing or inverting. This contraction also prevents regurgitation, or the backward flow of blood from the ventricles into the atrial cavities.
There are five papillary muscles in the heart: three in the right ventricle and two in the left ventricle. The right ventricle's papillary muscles are the anterior, posterior, and septal muscles, while the left ventricle's are the anterolateral and posteromedial muscles. The anterolateral papillary muscle typically has a single body or head, while the posteromedial muscle usually has two.
The papillary muscles can be affected by various conditions, including myocardial infarction, which can lead to rupture or dysfunction. Other abnormalities include fibrotic scarring, congenital malformations, and calcification in the case of advanced Barlow's disease.
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Papillary muscle rupture can be caused by myocardial infarction
The papillary muscles are endocardial structures located in the ventricles of the heart. There are five total papillary muscles in the heart: three in the right ventricle and two in the left ventricle. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae. The contraction of the papillary muscles prevents inversion or prolapse of the valves during ventricular contraction.
Papillary muscle rupture is a rare but severe complication that can occur following a myocardial infarction. Myocardial infarction refers to a heart attack, which is when the blood supply to the heart is blocked, often due to a blood clot. This interruption in blood flow can lead to damage or death of heart muscle cells. In the case of a myocardial infarction, the papillary muscles can be affected, leading to a rupture. This is more likely to occur in the posteromedial papillary muscle due to its single blood supply, provided by the posterior descending coronary artery. If the blood supply to this muscle is compromised during a myocardial infarction, the muscle can become weakened and rupture.
The rupture of a papillary muscle can lead to severe mitral valve regurgitation, where blood flows backward from the ventricle into the atrium. This can result in cardiogenic shock and pulmonary edema, which are life-threatening conditions that require immediate medical attention. The risk of rupture is higher in the first week after a myocardial infarction, especially with ST-segment elevation myocardial infarction.
The diagnosis of papillary muscle rupture after a myocardial infarction can be challenging. While transthoracic echocardiography is a useful tool for detecting mitral regurgitation, it may not always detect the rupture. More comprehensive imaging techniques, such as transesophageal echocardiography with a transgastric view, are often required for a definitive diagnosis.
The treatment for papillary muscle rupture involves urgent surgical intervention, as the mortality rate is high without timely surgery. Surgical correction, such as mitral valve replacement or repair, has significantly improved outcomes compared to medical therapy alone. However, the rarity of papillary muscle rupture means that published data is limited, and most series consist of single-center experiences with small sample sizes.
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They can be visualised using midesophageal views
The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) and contract to prevent inversion or prolapse of these valves on systole (or ventricular contraction). There are five papillary muscles in the heart; three in the right ventricle and two in the left ventricle.
Papillary muscle rupture can be caused by a myocardial infarction, and dysfunction can be caused by ischemia. In the case of advanced Barlow's disease, the papillary muscle may become calcified and restrict chordae and leaflet motion. Changes in papillary muscle morphology include fibrotic scarring, rupture, or congenital malformations. These changes are best observed on transgastric short-axis (0°) and longitudinal (80°) views.
A ruptured papillary muscle can be readily visualised using midesophageal views. Several midesophageal planes also provide an evaluation of the wall motion of segments adjacent to the base of the papillary muscle, which impacts its function. The midesophageal view is the standard starting view for most studies, with the omniplane angle at 0 degrees and no rotation. If the aortic valve is seen, the probe is inserted further. To obtain this view, the probe is advanced from the ME 4c view to the stomach and then anteflexed to contact the stomach wall and the inferior wall of the heart. This allows for the visualisation of the anterolateral and posteromedial papillary muscles.
The midesophageal view is also used to assess RV and LV function. Changes in rotation, along with changing the probe depth, can be used to assess the pulmonary veins in this view, as well as better visualise the atria, which are near-field structures.
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Frequently asked questions
The papillary muscles are thick bands and ridges of myocardium that project into the lumen of the cardiac ventricles. They are components of the cardiac muscle chambers that play a crucial role in the proper opening and closing of atrioventricular valves.
The papillary muscles are located in the ventricles of the heart. There are two in the left ventricle and three in the right ventricle.
The papillary muscles contract to close the atrioventricular valves and prevent the valves from prolapsing. This prevents regurgitation, which is the backward flow of ventricular blood into the atrial cavities.
