The chordae tendineae (tendinous cords), colloquially known as the heart strings, are inelastic cords of

fibrous connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tissue is ...

that connect the

papillary muscle 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) via the chordae tendineae and contract to prevent inversion or pro ...

s to the

tricuspid valve The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, at the superior portion of the right ventricle. The function of the valve is to allow blood to flow from the right atrium to the right ven ...

and the mitral valve in the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...

Structure

The chordae tendineae connect the

atrioventricular valves A heart valve is a one-way valve that allows blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow through the heart. A heart v ...

(

tricuspid The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, at the superior portion of the right ventricle. The function of the valve is to allow blood to flow from the right atrium to the right ven ...

and

mitral The mitral valve (), also known as the bicuspid valve or left atrioventricular valve, is one of the four heart valves. It has two cusps or flaps and lies between the left atrium and the left ventricle of the heart. The heart valves are all one-w ...

), to the

s within the ventricles. Multiple chordae tendineae attach to each leaflet or cusp of the valves. Chordae tendineae contain elastin in a delicate structure notably at their periphery.

Tendon of Todaro

The ''tendon of Todaro'' is a continuation of the Eustachian valve of the inferior vena cava and the valve of the coronary sinus. Along with the opening of the coronary sinus and the septal cusp of the tricuspid valve, it makes up

Koch's triangle Koch's triangle, named after the German pathologist Walter Koch, is an anatomical area located in the superficial paraseptal endocardium of the right atrium, which its boundaries are the coronary sinus orifice, tendon of Todaro, and septal leaf ...

. The apex of Koch's triangle is the location of the

atrioventricular node The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart. The AV node lies at the lower back section of t ...

Function

During

atrial The atrium ( la, ātrium, , entry hall) is one of 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 valves. There are two at ...

systole, blood flows from the atria to the ventricles down the

pressure gradient In atmospheric science, the pressure gradient (typically of air but more generally of any fluid) is a physical quantity that describes in which direction and at what rate the pressure increases the most rapidly around a particular location. The p ...

. Chordae tendineae are relaxed because the

atrioventricular valve A heart valve is a one-way valve that allows blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow through the heart. A heart v ...

s are forced open. When the ventricles of the heart contract in ventricular systole, the increased blood pressures in both chambers push the AV valves to close simultaneously, preventing backflow of blood into the atria. Since the blood pressure in atria is much lower than that in the ventricles, the flaps attempt to evert to the low pressure regions. The chordae tendineae prevent this

prolapse In medicine, prolapse is a condition in which organs fall down or slip out of place. It is used for organs protruding through the vagina, rectum, or for the misalignment of the valves of the heart. A spinal disc herniation is also sometimes ca ...

by becoming tense, which pulls on the flaps, holding them in closed position.

Clinical significance

Ruptured chordae tendineae

Valvular heart disease Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart (the aortic and mitral valves on the left side of heart and the pulmonic and tricuspid valves on the right side of heart). These ...

can lead to ruptured chordae tendineae. This can cause severe

mitral insufficiency Mitral regurgitation (MR), also known as mitral insufficiency or mitral incompetence, is a form of valvular heart disease in which the mitral valve is insufficient and does not close properly when the heart pumps out blood.

Parachute mitral valve

''Parachute mitral valve'' occurs when all the chordae tendineae of the mitral valve attach to a single papillary muscle. This causes

mitral valve stenosis Mitral stenosis is a valvular heart disease characterized by the narrowing of the opening of the mitral valve of the heart. It is almost always caused by rheumatic valvular heart disease. Normally, the mitral valve is about 5 cm2 during d ...

at an early age. It is a rare

congenital heart defect A congenital heart defect (CHD), also known as a congenital heart anomaly and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascul ...

. Although it often causes

, it may not present any symptoms.

Additional images

File:Muscolopapillarex.jpg, Papillary muscles and chordae tendineae File:UOTW 75 - Ultrasound of the Week 1.webm, Ultrasound showing redundant chordae tendineae

References

{{Authority control Cardiac anatomy