'antiarrhythmic' originates from Greek elements: the prefix 'anti-' (Greek 'anti') meaning 'against' and 'arrhythmia' (from Greek 'arrhythmia'), where 'a-' meant 'without' and 'rhythmos' meant 'rhythm'.

'antiarrhythmic' was formed in modern medical/Latin usage (New Latin/modern coinage) from 'anti-' + 'arrhythmia' (itself from Greek 'arrhythmia') and entered English as the adjective/noun 'antiarrhythmic' in medical contexts.

Initially coined to mean 'acting against irregular rhythm'; its core meaning has remained focused on countering or treating irregular heart rhythms, though it has been applied to various drug classes and mechanisms over time.