The chordae tendineae are small, cord-like structures found within the heart, often called “heart strings.” These fibrous cords, primarily composed of collagen and elastin, play a role in the heart’s ability to pump blood efficiently throughout the body. Their strength and flexibility are important for withstanding the forces generated during each heartbeat.
Anatomical Placement
The chordae tendineae are located within the heart’s lower chambers, the ventricles. They connect the heart’s atrioventricular (AV) valves to small muscular projections called papillary muscles. On the right side, they attach to the tricuspid valve, and on the left, to the mitral valve. Each valve leaflet receives attachments from multiple chordae tendineae. The papillary muscles, anchoring these cords, originate from the inner ventricular walls.
Critical Role in Heart Function
The main function of the chordae tendineae is to prevent the AV valve leaflets from inverting or bulging backward into the atria when the ventricles contract. During ventricular contraction, blood pressure inside these chambers rises. This increased pressure would otherwise force the valve flaps open, allowing blood to flow backward into the atria. Instead, the chordae tendineae become taut, pulling on the valve leaflets and holding them in a closed position.
The coordinated action between the papillary muscles and the chordae tendineae is important for maintaining one-way blood flow. As the ventricular muscles contract, the papillary muscles simultaneously contract, maintaining tension on the chordae tendineae. This synchronization ensures that the tricuspid and mitral valves remain sealed, preventing blood from regurgitating into the atria. This mechanism maintains valve integrity, ensuring blood is efficiently propelled forward into the major arteries with each heartbeat.
When Chordae Tendineae Malfunction
Damage or dysfunction of the chordae tendineae can lead to heart conditions, most commonly valve regurgitation. This occurs when the valves become “leaky,” allowing blood to flow backward into the atria because the leaflets cannot close completely. The heart must then work harder to pump the same amount of blood, which can lead to symptoms such as shortness of breath, fatigue, and heart palpitations. If left unaddressed, this increased workload can eventually result in heart failure.
Causes and Treatment
Various factors can cause chordae tendineae damage. Degenerative conditions, such as mitral valve prolapse or myxomatous degeneration, can weaken the cords over time. Infections, particularly infective endocarditis, may also lead to their tearing or rupture. Less common causes include trauma to the chest or certain congenital defects. When damage occurs, medical intervention, often involving valve repair or replacement surgery, may be necessary to restore heart function. Surgical techniques can involve repairing the existing cords, transferring healthy ones, or replacing them with artificial materials.