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

The clearest example sits in Publicis Groupe’s 2024 pitch for the Pfizer business, where Liu was selected to join the core pitch team and led a nationwide consumer-testing survey of 350 at-risk atrial fibrillation patients under a three-day deadline. —William Jones, USA Today, 9 June 2026

Hogan had been suffering from numerous heath issues before his death, including leukemia, an irregular atrial fibrillation, pneumonia, and kidney failure, family members told investigators. —Charisma Madarang, Rolling Stone, 8 June 2026

According to the medical records, the former pro wrestler had a history of leukemia and atrial fibrillation, a common disorder that causes irregular heartbeats. —Mekishana Pierre, Entertainment Weekly, 6 June 2026

Prevention includes managing high blood pressure, diabetes, atrial fibrillation and other risk factors. —Angelica Stabile, FOXNews.com, 30 May 2026

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