The heart operates as a highly efficient pump, relying on precisely timed mechanical events to circulate blood throughout the body. Within its four chambers, strong cord-like structures known as the chordae tendineae play a necessary role in maintaining this flow. A sudden failure of these structures, typically through rupture, represents a serious mechanical failure within the circulatory system. This event instantly compromises the heart’s ability to move blood forward, leading to a life-threatening medical emergency.
The Function of the Chordae Tendineae
These fibrous strands connect the muscular projections, called papillary muscles, on the ventricular walls to the leaflets of the atrioventricular valves. They are composed of strong collagen fibers, providing the tensile strength required to resist the pressure generated during heart contraction.
Their primary mechanical purpose is to anchor the valve leaflets securely when the ventricles contract (systole). This anchoring ensures that the valve leaflets close tightly and do not flip backward into the upper chambers (atria) when ventricular pressure spikes. The cords prevent the valve from prolapsing backward under the force of the blood being expelled from the ventricle.
Immediate Consequences of Rupture
When one or more chordae tendineae rupture, the support structure for a section of the valve leaflet is lost. This failure leads to acute regurgitation, most often involving the mitral valve on the left side of the heart. The unsupported valve leaflet flips back into the left atrium during ventricular contraction, allowing a significant volume of blood to flow backward instead of moving forward into the aorta.
This sudden backflow causes an immediate pressure overload in the left atrium and the veins leading to it. The pressure quickly transmits back into the pulmonary circulation, causing fluid to leak into the air sacs of the lungs. This condition, known as flash pulmonary edema, results in severe shortness of breath and a decline in oxygen levels. The heart struggles to maintain forward flow due to the severe leak, potentially leading to cardiogenic shock, where the heart cannot pump enough blood to meet the body’s needs.
Primary Causes of Damage
Rupture often stems from an underlying disease process that weakens the collagen fibers of the chords. The most frequent cause is degenerative valve disease, specifically myxomatous degeneration, often seen in individuals with Mitral Valve Prolapse. In this condition, the valve tissue becomes floppy and thickened, causing the connected chordae to stretch or fail spontaneously under normal pressure.
Infective endocarditis is another cause, where pathogens colonize the valve, forming vegetations that erode and destroy the chordal tissue. Less common causes include ischemic events, such as a heart attack that damages the blood supply to the papillary muscles, causing them to weaken. Blunt chest trauma, although rare, can also generate enough force to mechanically snap an otherwise healthy chord.
Treatment and Repair Options
A ruptured chordae tendineae causing acute, severe regurgitation requires immediate medical stabilization. Initial management aims to reduce the pressure against which the heart is pumping and manage fluid overload. Medications such as diuretics remove excess fluid, while vasodilators temporarily lower blood pressure and decrease the resistance the heart must overcome.
Definitive treatment is surgical intervention to fix the mechanical defect. The preferred approach is mitral valve repair, which is favored over replacement because it preserves the patient’s own valve and maintains better long-term heart function. Surgeons often use durable materials like expanded polytetrafluoroethylene (ePTFE) sutures to create new, artificial chordae, re-anchoring the loose valve leaflet to the papillary muscle.
If the valve is too extensively damaged, the alternative is valve replacement, involving the implantation of a mechanical or biological prosthetic valve. Modern techniques emphasize preserving the subvalvular apparatus, including the remaining chordae and papillary muscles, even during replacement.