Final answer:
An abnormal rhythm in a patient is called an arrhythmia, with tachycardia and bradycardia being subtypes for fast and slow heart rates, respectively.
Step-by-step explanation:
If a patient has an abnormal rhythm, it is called an arrhythmia. This term encompasses conditions where the heartbeat is too fast, known as tachycardia, or too slow, referred to as bradycardia. Arrhythmia, also known as cardiac arrhythmia or heart arrhythmia, indicates any irregularity in the heart's rhythm that deviates from the normal range of 60-100 beats per minute (bpm) for adults.
Tachycardia is when the resting heart rate is above 100 bpm and can be detected in individuals under different conditions, including extreme stress or during pregnancy, but it's not normal in a resting patient. Conversely, bradycardia occurs when the resting heart rate drops below 60 bpm. These conditions may require medical interventions such as medications, pacemakers, or defibrillators, depending on their severity and underlying causes.