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

Several heart disorders also increase stroke risk, including coronary artery disease, as well as heart valve defects, atrial fibrillation and congestive heart failure. —Katia Hetter, CNN, 7 Feb. 2025

Congestive heart failure was the most common complication, occurring in 36 percent of people, followed by atrial fibrillation (21 percent), cardiogenic shock (7 percent), stroke (5 percent), and heart attack (3 percent). —Emily Kay Votruba, EverydayHealth.com, 15 May 2025

It's estimated that atrial fibrillation, the most common type of arrhythmia, will affect 12.1 million Americans by 2030. —Simon Spichak, Health, 2 May 2025

The irregular heartbeat — ventricular fibrillation (v-fib) — prevents blood from pumping to the brain causing a person to faint or sudden cardiac death. —Vanessa Etienne, People.com, 30 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