The phrase “heart strings” has a dual nature, referring to both a precise physical structure within the heart and a deeply rooted linguistic metaphor. While the common usage, such as “tugging at the heartstrings,” suggests a purely emotional concept, the body does contain structures that resemble actual strings. Understanding the anatomical reality of these structures provides insight into the mechanics that allow the heart to function.
The Literal Heart Strings: Anatomy and Structure
The structures colloquially called “heart strings” are medically known as the chordae tendineae. These are thin, fibrous cords of inelastic connective tissue found inside the heart’s lower chambers, the ventricles. Composed primarily of strong collagen fibers, they have a tough, string-like appearance.
The chordae tendineae are part of the heart’s valve system. They connect the papillary muscles, which protrude from the ventricular walls, to the leaflets of the two atrioventricular valves: the tricuspid valve (right ventricle) and the mitral valve (left ventricle). Multiple cords attach to each valve leaflet, ensuring a secure connection between the valve and the ventricular wall.
How the Heart Strings Function
The primary job of the chordae tendineae is to maintain the integrity of the heart valves under pressure. When the ventricles contract during systole, the blood pressure inside them increases. This pressure surge pushes the valve leaflets closed, preventing blood from flowing backward into the atria.
If the cords were absent, the pressure would cause the valve leaflets to prolapse, or balloon backward. The chordae tendineae become tense during contraction, acting like tethers that hold the leaflets firmly closed. This action, assisted by the papillary muscles, ensures that blood is forced forward out of the ventricles and into the main arteries.
The Origin of the Metaphorical Phrase
The common phrase “tugging at the heartstrings,” which evokes a strong emotional reaction, predates modern anatomical knowledge. Its linguistic origin is rooted in older philosophical beliefs. In medieval times, it was believed that thread-like structures physically supported the heart within the chest.
These supposed structures were thought to be directly connected to a person’s deepest feelings. Profound affection or sympathy was conceptualized as an external force gently pulling or “tugging” at these internal strings. The metaphorical use of “heartstrings” represents a person’s inner emotional core.
When the Heart Strings Fail
Damage to the chordae tendineae is a serious medical event that directly compromises heart function. If one or more of these cords rupture, the corresponding valve leaflet loses its tether and cannot close properly during ventricular contraction. This immediate failure results in severe regurgitation, where blood flows backward into the atrium instead of moving forward through the circulatory system.
This acute failure can be caused by various factors, including infections like infective endocarditis, degenerative conditions such as mitral valve prolapse, or physical trauma to the chest. The sudden loss of proper valve function results in acute heart failure, which can manifest with symptoms like extreme shortness of breath, fatigue, and general hemodynamic instability. Because of the severity of the condition, ruptured chordae tendineae often require urgent medical intervention, typically involving surgical repair of the valve and its cords or, if the damage is too extensive, replacement of the valve entirely.