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

Like doctors stopping a patient’s heart to cure atrial fibrillations, a brief, brutal trade war could have Americans paying less and owning more. —Chris Stirewalt, The Hill, 8 Apr. 2025

Atrial fibrillation significantly increases the risk of stroke, but even after researchers removed stroke patients from the analysis, the association between afib and dementia remained unchanged. —Tom Gavin, EverydayHealth.com, 1 Apr. 2025

The Charge can also be used to an ECG and the Fitbit app, will alert you to any atrial fibrillation (AFib) events. . —Larry Magid, Mercury News, 28 Mar. 2025

After further inspecting the device, Jarrell and investigators noticed Hackman’s heart also showed an atrial fibrillation, or irregular heartbeat, the following day, on Feb. 18. —Rick Jervis, USA TODAY, 9 Mar. 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