fibrillation

American  

[fib-ruh-ley-shuhn, fahy-bruh-] / ˌfɪb rəˈleɪ ʃən, ˌfaɪ brə- /

noun

1. the formation of fibrils, or fine fibers or filaments.

2. Pathology. uncontrolled twitching or quivering of muscle fibers, such as those of the heart.

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fibrillation British  

/ ˌfaɪbrɪˈleɪʃən, ˌfɪb- /

noun

1. a local and uncontrollable twitching of muscle fibres, esp of the heart, not affecting the entire muscle. Atrial fibrillation results in rapid and irregular heart and pulse rate. In ventricular fibrillation , the heart stops beating

2. irregular twitchings of the muscular wall of the heart, often interfering with the normal rhythmic contractions

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fibrillation Scientific  

/ fĭb′rə-lā′shən /

1. A rapid twitching of muscle fibers, as of the heart, that is caused by the abnormal discharge of electrical nerve impulses. Ventricular fibrillation is life-threatening.

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Etymology

Origin of fibrillation

First recorded in 1830–40; fibrillate + -ion

Compare meaning

How does fibrillation compare to similar and commonly confused words? Explore the most common comparisons:

• fibrillation vs. fasciculation

Example Sentences

See Examples For:

fibrillation

Recent analyses based on participant-reported health information found that consuming 1-3 cups of caffeinated coffee per day was not associated with a higher risk of atrial fibrillation or abnormal heart rhythm.

From Science Daily ● Jul. 22, 2026

Caffeine also blocks a substance that can cause atrial fibrillation, an arrhythmia that can lead to strokes.

From The Wall Street Journal ● Jul. 20, 2026

Atrial fibrillation is an irregular heart rhythm, while heart failure means the heart cannot pump enough blood to meet the body's needs.

From Science Daily ● Jul. 12, 2026

According to Civello, the next wave — in which wearables can detect conditions like atrial fibrillation, hypertension and sleep apnea — is happening now.

From MarketWatch ● May 28, 2026

Then he handed the glass to Camilla and, left hand free, reached down and turned the fibrillation into the opening notes of a Scott Joplin rag.

From "The Secret History" by Donna Tartt