Final answer:
The medical term for a lack of rhythm of the heartbeat is arrhythmia. Arrhythmia is a group of conditions in which the heartbeat is irregular, too fast, or too slow.
Step-by-step explanation:
The medical term for a condition in which there is a lack of rhythm of the heartbeat is arrhythmia. Arrhythmia is a group of conditions in which the heartbeat is irregular, too fast, or too slow. Symptoms of arrhythmia may include palpitations, lightheadedness, shortness of breath, or chest pain. Treatment for arrhythmia depends on the underlying cause and may include medications, lifestyle changes, or medical procedures like a pacemaker.