Final answer:
Arrhythmia, also called dysrhythmia, refers to an irregularity in the heart's rhythm, including tachycardia when above 100 bpm, or bradycardia when below 60 bpm. Symptoms may include palpitations or chest pain, and serious cases may require intervention like a defibrillator or pacemaker.
Step-by-step explanation:
The medical term for irregularity in the rate or rhythm of the heart is arrhythmia, which is also known as dysrhythmia. When the heartbeat is faster than normal, exceeding 100 beats per minute in adults, it is referred to as tachycardia. Conversely, if the heart rate is slower than normal, falling below 60 beats per minute, it is termed bradycardia.
These conditions can exist without symptoms; however, when they are present, symptoms might include palpitations, lightheadedness, passing out, shortness of breath, or chest pain. Cardiac arrhythmias can be serious, potentially leading to stroke, heart failure, or even sudden death. Treatments such as the use of a cardiac defibrillator or the implantation of a pacemaker may be necessary to normalize heart rhythm, particularly in chronic cases where the heart maintains a junctional rhythm.