What is the life-threatening condition of the heart where the muscle fibers contract irregularly called?

Fibrillation is the life-threatening condition of the heart characterized by a rapid and irregular pattern of contractions in the heart muscle fibers. This erratic electrical activity can prevent the heart from effectively pumping blood, leading to inadequate blood supply to vital organs. In cases of atrial fibrillation, for instance, the upper chambers of the heart (the atria) quiver rather than contract effectively, which can lead to complications such as blood clots or stroke.

This condition requires immediate medical attention, often necessitating interventions like defibrillation, which is used to restore a normal rhythm. Understanding fibrillation is critical for recognizing its serious implications in a clinical setting, as swift action is essential for a favorable outcome in affected patients.