fibrillation

noun

fi·​bril·​la·​tion ˌfi-brə-ˈlā-shən  ˌfī- 

1

: an act or process of forming fibers or fibrils

2

a

: a muscular twitching involving individual muscle fibers acting without coordination

b

: very rapid irregular contractions of the muscle fibers of the heart resulting in a lack of synchronism between heartbeat and pulse

Examples of fibrillation in a Sentence

Recent Examples on the Web

Higher doses of fish oil may increase the risk of atrial fibrillation. —Amy Brownstein, Verywell Health, 6 May 2025

Weed has also been linked to cardiac arrhythmias such as atrial fibrillation; myocarditis — an inflammation of the heart muscle — spasms of the heart’s arteries and a higher risk of heart failure. —Sandee Lamotte, CNN Money, 5 May 2025

The legacy way to treat conditions such as atrial fibrillation used extreme heat (radiofrequency ablation) or cold (cryoablation). —Kevin Stankiewicz, CNBC, 16 Apr. 2025

This machine learning approach requires large bio-signal datasets in which instances of atrial fibrillation are labeled. —Eloy Geenjaar, The Conversation, 10 Apr. 2025

Word History

First Known Use

1845, in the meaning defined at sense 1

Rhymes for fibrillation

• abdication
• aberration
• abjuration
• abnegation
• abrogation
• acceptation
• acclamation
• acclimation
• accusation
• activation
• actuation
• acylation

Medical Definition

fibrillation

noun

fi·​bril·​la·​tion ˌfib-rə-ˈlā-shən  ˌfīb- 

1

: an act or process of forming fibers or fibrils

2

a

: a muscular twitching involving individual muscle fibers acting without coordination

b

: very rapid irregular contractions of the muscle fibers of the heart resulting in a lack of synchronism between heartbeat and pulse see atrial fibrillation, ventricular fibrillation