Lacking rhythm or characterized by irregular rhythm; relating to or affected by arrhythmia.
From Greek 'a-' (without) + 'rhythmikos' (rhythmic), creating an adjective form describing the absence of regular rhythm.
While 'rhythmic' makes you think of drums and music, 'arrythmic' in medical contexts is actually concerning—an arrythmic heartbeat is one of those medical problems that doctors can now fix with pacemakers!
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