The chordae tendineae (: chorda tendinea) or tendinous cords, colloquially known as the heart strings, are inelastic cords of fibrous connective tissue 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 ...

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 vent ...

and the

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

in the

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

Structure

The chordae tendineae connect the atrioventricular valves ( tricuspid 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 of heart valves, cusps or flaps and lies between the atrium (heart), left atrium and the ventricle (heart), ...

), to the

s within the ventricles. Multiple chordae tendineae attach to each leaflet or cusp of the valves. Chordae tendineae contain

elastin Elastin is a protein encoded by the ''ELN'' gene in humans and several other animals. Elastin is a key component in the extracellular matrix of gnathostomes (jawed vertebrates). It is highly Elasticity (physics), elastic and present in connective ...

in a delicate structure notably at their periphery.

Function

During

atrial The atrium (; : atria) 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. ...

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

pressure gradient In hydrodynamics and hydrostatics, 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 locat ...

. Chordae tendineae are relaxed because the atrioventricular valves are forced open. When the ventricles of the heart contract in ventricular systole, the increased

blood pressure Blood pressure (BP) is the pressure of Circulatory system, circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term ...

s in both chambers push the AV valves to close simultaneously, preventing the backflow of blood into the atria. Since the blood pressure in the 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 by becoming tense, which pulls on the flaps, holding them in a closed position.

Clinical significance

Ruptured chordae tendineae

Valvular heart disease can lead to ruptured chordae tendineae. This can cause severe mitral insufficiency.

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 at an early age. It is a rare

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

. Although it often causes mitral insufficiency, it may not present any

symptom Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

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