Escape rhythm is a term used to describe an irregularity in the heart rhythm that occurs when the heart's normal pacemaker fails to control the heartbeat. There are many synonyms for this term, including ectopic beat, arrhythmia, off-beat, palpitation, missed beat, and extrasystole. Ectopic beat refers to a heartbeat that originates from a location in the heart other than the normal pacemaker. Arrhythmia is a broader term that encompasses all types of irregular heartbeats. Off-beats and palpitations refer to irregular heartbeats that can be felt by the patient. Missed beats occur when a heartbeat is skipped. Extrasystoles refer to the occurrence of a premature heartbeat. All of these terms are used to describe variations in heart rhythm that can occur in both healthy and diseased individuals.