What does arrhythmia mean?
Arrhythmia refers to any abnormality in the rhythm or rate of the heartbeat, occurring when the heart's electrical impulses misfire and cause it to beat too fast, too slow, or irregularly. It is a noun used almost exclusively in medical and health contexts, ranging from everyday wellness discussions to specialist cardiology. Some arrhythmias are harmless and fleeting, triggered by caffeine, stress, or dehydration, while others — such as atrial fibrillation — are serious conditions requiring treatment because they increase the risk of stroke or cardiac arrest. The word derives from Greek roots meaning 'without rhythm', with the prefix 'a-' indicating absence, though medically it denotes disordered rather than absent rhythm. Its adjective form, 'arrhythmic', extends more broadly to anything lacking regular rhythm. Because it appears frequently in medical reporting, patient literature, and health journalism, arrhythmia is a useful term for anyone reading about cardiovascular health.
nounAn abnormality in the rate or rhythm of the heartbeat, in which the heart beats too quickly, too slowly, or irregularly.
- An abnormality in the rate, regularity, or sequence of heartbeats.
"The cardiologist detected an arrhythmia during the patient's stress test."
"Atrial fibrillation is one of the most common types of arrhythmia seen in older adults."
"Caffeine and stress can occasionally trigger a brief arrhythmia in people with otherwise healthy hearts."
Standard English plural, formed by adding -s. Used when referring to multiple distinct episodes or types.
"Patients with structural heart disease may experience several different arrhythmias over time."
Despite its spelling, 'arrhythmia' literally means 'no rhythm' — from Greek — but doctors kept the double 'rr' to avoid implying the heart stops entirely.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of arrhythmia
The word arrhythmia comes from Greek: the privative prefix 'a-' ('without') combined with 'rhythmos' ('measured motion, rhythm'), so it originally meant 'lack of rhythm'. It entered modern medical usage through New Latin in the nineteenth century as physicians sought precise terminology for disordered heart rhythms. It shares its root with words like rhythmic, rhythmicity, and dysrhythmia, all built on the same Greek stem.
Related word forms
How arrhythmia is actually used
Arrhythmia is a formal medical term used primarily in clinical and health contexts. It is countable when referring to specific instances ('an arrhythmia') and uncountable when referring to the general condition. The plural is 'arrhythmias'. It carries no inherent emotional connotation beyond its clinical seriousness.
Easily confused with arrhythmia
Dysrhythmia is a broader medical term for any abnormal rhythm (including of the brain, stomach, or muscles), while arrhythmia specifically refers to an irregularity in the heart's rhythm; the two are often used interchangeably for cardiac cases.