| Pectinate muscles | |
|---|---|
 Section of the heart showing the ventricular septum. (Pectinate muscles labeled at center left.) | |
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| Details | |
| Identifiers | |
| Latin | musculi pectinati atrii dextri, musculi pectinati atrii sinistri |
| TA98 | A12.1.01.008 A12.1.03.003 |
| TA2 | 4024, 4056 |
| FMA | 12226 |
| Anatomical terminology | |
The pectinate muscles (musculi pectinati) are parallel muscular ridges in the walls of the atria of the heart.
Behind the crest (crista terminalis) of the right atrium the internal surface is smooth. [1] Pectinate muscles make up the part of the wall in front of this, the right atrial appendage.[ citation needed ]
In the left atrium, the pectinate muscles are confined to the inner surface of its atrial appendage. [1] They tend to be fewer and smaller than in the right atrium. This is due to the embryological origin of the auricles, which are the true atria. Some sources cite that the pectinate muscles are useful in increasing the power of contraction without increasing heart mass substantially.[ citation needed ]
Pectinate muscles of the atria are different from the trabeculae carneae, which are found on the inner walls of both ventricles.[ citation needed ] The pectinate muscles originate from the crista terminalis.[ citation needed ]
The pectinate muscles are so-called because of their resemblance to the teeth of a comb, as in pecten.[ citation needed ]
The heart is a muscular organ found in most animals. This organ pumps blood through the blood vessels. Heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest, called the mediastinum.
A ventricle is one of two large chambers located toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper heart that is smaller than a ventricle. Interventricular means between the ventricles, while intraventricular means within one ventricle.
The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four main pulmonary veins, two from each lung that drain into the left atrium of the heart. The pulmonary veins are part of the pulmonary circulation.
Atrial flutter (AFL) is a common abnormal heart rhythm that starts in the atrial chambers of the heart. When it first occurs, it is usually associated with a fast heart rate and is classified as a type of supraventricular tachycardia. Atrial flutter is characterized by a sudden-onset (usually) regular abnormal heart rhythm on an electrocardiogram (ECG) in which the heart rate is fast. Symptoms may include a feeling of the heart beating too fast, too hard, or skipping beats, chest discomfort, difficulty breathing, a feeling as if one's stomach has dropped, a feeling of being light-headed, or loss of consciousness.
Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this does not naturally close after birth it is referred to as a patent (open) foramen ovale (PFO). It is common in patients with a congenital atrial septal aneurysm (ASA).
AV-nodal reentrant tachycardia (AVNRT) is a type of abnormal fast heart rhythm. It is a type of supraventricular tachycardia (SVT), meaning that it originates from a location within the heart above the bundle of His. AV nodal reentrant tachycardia is the most common regular supraventricular tachycardia. It is more common in women than men. The main symptom is palpitations. Treatment may be with specific physical maneuvers, medications, or, rarely, synchronized cardioversion. Frequent attacks may require radiofrequency ablation, in which the abnormally conducting tissue in the heart is destroyed.
Cardiac catheterization is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes.
The atrium is one of the two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular mitral and tricuspid heart valves.
Catheter ablation is a procedure that uses radio-frequency energy or other sources to terminate or modify a faulty electrical pathway from sections of the heart of those who are prone to developing cardiac arrhythmias such as atrial fibrillation, atrial flutter and Wolff-Parkinson-White syndrome. If not controlled, such arrhythmias increase the risk of ventricular fibrillation and sudden cardiac arrest. The ablation procedure can be classified by energy source: radiofrequency ablation and cryoablation.
The mini-maze procedures are cardiac surgery procedures intended to cure atrial fibrillation (AF), a common disturbance of heart rhythm. They are procedures derived from the original maze procedure developed by James Cox, MD.
In the heart's conduction system, Bachmann's bundle is a branch of the anterior internodal tract that resides on the inner wall of the left atrium. It is a broad band of cardiac muscle that passes from the right atrium, between the superior vena cava and the ascending aorta. Bachmann's bundle is, during normal sinus rhythm, the preferential path for electrical activation of the left atrium. It is therefore considered to be part of the "atrial conduction system" of the heart.
The small cardiac vein, also known as the right coronary vein, is a coronary vein that drains parts of the right atrium and right ventricle of the heart. Despite its size, it is one of the major drainage vessels for the heart.
The sinus venarum is the portion of the right atrium in the adult human heart where the inner surface of the right atrium is smooth, whereas the rest of the inner surface is rough (trabeculated) due to the presence of pectinate muscles. The sinus venarum represents the portion of the adult heart that develops from the right sinus horn of the foetal sinus venosus. The sinus venarum is demarcated from the rest of the right atrium by the crista terminalis (internally) and the sulcus terminalis (externally).
The trabeculae carneae are rounded or irregular muscular columns which project from the inner surface of the right and left ventricle of the heart. These are different from the pectinate muscles, which are present in the atria of the heart. In development, trabeculae carneae are among the first of the cardiac structures to develop in the embryonic cardiac tube. Further, throughout development some trabeculae carneae condense to form the myocardium, papillary muscles, chordae tendineae, and septum.
The crista terminalis is a vertical ridge on the posterolateral inner surface of the adult right atrium extending between the superior vena cava, and the inferior vena cava. The crista terminalis denotes where the junction of the embryologic sinus venosus and the right atrium occurred during embryonic development. It forms a boundary between the rough trabecular portion and the smooth, sinus venosus-derived portion of the internal surface of the right atrium. The sinoatrial node is located within the crista terminalis.
Atrial septostomy is a surgical procedure in which a small hole is created between the upper two chambers of the heart, the atria. This procedure is primarily used to palliate dextro-Transposition of the great arteries or d-TGA, a life-threatening cyanotic congenital heart defect seen in infants. It is performed prior to an arterial switch operation. Atrial septostomy has also seen limited use as a surgical treatment for pulmonary hypertension. The first atrial septostomy was developed by Vivien Thomas in a canine model and performed in humans by Alfred Blalock. The Rashkind balloon procedure, a common atrial septostomy technique, was developed in 1966 by American cardiologist William Rashkind at the Children's Hospital of Philadelphia.
Arrhythmias, also known as cardiac arrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults – is called tachycardia, and a resting heart rate that is too slow – below 60 beats per minute – is called bradycardia. Some types of arrhythmias have no symptoms. Symptoms, when present, may include palpitations or feeling a pause between heartbeats. In more serious cases, there may be lightheadedness, passing out, shortness of breath, chest pain, or decreased level of consciousness. While most cases of arrhythmia are not serious, some predispose a person to complications such as stroke or heart failure. Others may result in sudden death.
The heart is a muscular organ situated in the mediastinum. It consists of four chambers, four valves, two main arteries, and the conduction system. The left and right sides of the heart have different functions: the right side receives de-oxygenated blood through the superior and inferior venae cavae and pumps blood to the lungs through the pulmonary artery, and the left side receives saturated blood from the lungs.
Intracardiac echocardiography (ICE) is a specialized form of echocardiography that utilizes an ultrasound-tipped catheter to perform imaging of the heart from within the heart. Unlike transthoracic echocardiography (TTE), ICE is not limited by body habitus. An ICE catheter is inserted into the body, typically, through the femoral vein and advanced into the heart.
Ganglionated plexi (GP) comprise the intrinsic cardiac autonomic nervous system composed of autonomic ganglia of the heart atrium and ventricles. The GP are embedded in the epicardial fat pads, consisting of only a few neurons or as many as 400 neurons. GP are spatially close to the pulmonary veins, such that pulmonary vein isolation necessarily affects the GP. GP has been shown to be a contributor to atrial fibrillation (AFib), such that ablation of the GP has been a strategy for treatment of AFib. Pulsed field ablation has shown to be an AFib ablation strategy which effectively destroys the GP. GP ablation alone has been shown to eliminate AFib in approximately three-quarter of AFib patients.
This article incorporates text in the public domain from page 529 of the 20th edition of Gray's Anatomy (1918)
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