The human heart functions as an efficient pump, circulating blood throughout the body. Its design includes four valves that ensure blood flows in one direction, preventing backward leakage. The mitral valve, located on the left side of the heart, works with specialized structures called chordae tendineae. Their coordinated action ensures proper blood circulation.
Anatomy and Location
The chordae tendineae are strong, fibrous cords, often described as “heart strings.” These cord-like structures are primarily made of dense regular connective tissue, containing strong collagen protein fibers and some elastin for elasticity. They are located within the left ventricle of the heart, connecting the leaflets of the mitral valve to small muscular projections called papillary muscles.
The mitral valve, also known as the bicuspid valve or left atrioventricular valve, is one of the heart’s four valves. It is positioned between the left atrium and the left ventricle. This valve consists of two leaflets, an anterior and a posterior cusp, to which the chordae tendineae attach. The papillary muscles arise from the inner walls of the left ventricle and extend towards the valve leaflets.
Role in Heart Function
The primary function of the chordae tendineae is to prevent the mitral valve leaflets from prolapsing, or bulging backward, into the left atrium during ventricular contraction. When the left ventricle contracts to pump oxygenated blood into the aorta, pressure builds within the chamber. Without the chordae tendineae, this pressure would force the valve leaflets to invert, allowing blood to flow backward into the left atrium.
As the left ventricle contracts, the papillary muscles also contract. This synchronized contraction pulls on the chordae tendineae, which hold the mitral valve leaflets firmly in place. This action creates a tight seal, ensuring blood flows only forward into the aorta and not back into the left atrium. This mechanism is comparable to parachute strings preventing the canopy from inverting in strong winds.
When Things Go Wrong
Damage to the chordae tendineae can impair mitral valve function, leading to various heart conditions. Common issues include rupture, elongation, or thickening of these fibrous cords. Rupture can occur due to age-related degeneration, infections like endocarditis, or trauma, impacting valve integrity. Elongation or thickening of the chordae can also compromise their ability to support the valve leaflets.
Such damage commonly results in mitral valve dysfunction, including mitral regurgitation or mitral valve prolapse. Mitral regurgitation occurs when the leaflets do not close completely, allowing blood to leak backward into the left atrium during ventricular contraction. Mitral valve prolapse involves the bulging of one or both leaflets into the left atrium. These conditions reduce the heart’s pumping efficiency, as a portion of the blood is forced backward instead of forward.
Symptoms of compromised chordae tendineae include shortness of breath during exertion and fatigue. Patients may also experience heart murmurs, which are abnormal sounds heard during a heartbeat, caused by turbulent blood flow through the faulty valve. In severe cases, the heart may become enlarged, and there could be increased pressure in the left atrium and pulmonary circulation, leading to further complications.