Plain English Meaning

An abnormal heartbeat — beating too fast, too slow, or in an irregular pattern instead of a steady rhythm.

Full Definition

An irregular rhythm of the heartbeat, in which the heart beats too fast, too slow, or in an uneven pattern. In an aviation context, cardiac arrhythmia is one of the medical effects associated with exposure to elevated carbon dioxide levels, such as those produced by sublimating dry ice in an enclosed cabin.

Context Anchor

Seen in aeromedical and safety discussions, including the hazards of carrying dry ice in an aircraft, because dry ice gives off carbon dioxide gas.

Derivation

From Greek 'kardia' (heart) and 'arrhythmia' (lack of rhythm) — literally 'no rhythm of the heart.' The 'a-' prefix means 'without,' and 'rhythmos' means 'measured flow.' The word itself names the problem: the heart has lost its steady beat.