Pertaining to, or composed of, fibres.

The rapid, irregular, and unsynchronized contraction of the muscle fibers of the heart.

(intransitive) To make rapid irregular movements.

A fine fibre or filament / (biology) Any fine, filamentous structure in animals or plants

plural of fibril

present participle of fibrillate

Splitting into fibrils or fibres. / Of a muscle, especially in the heart: undergoing fibrillation; quivering.

simple past tense and past participle of fibrillate

Having fibrils

Third-person singular simple present indicative form of fibrillate