Final answer:
Extra beats, including premature atrial, ventricular, and junctional contractions, are types of arrhythmias that are not life-threatening and typically do not require treatment.
Step-by-step explanation:
A rhythm disturbance that is not life-threatening is known as extra beats. These can include premature atrial contractions, premature ventricular contractions, and premature junctional contractions. Extra beats are generally considered benign and are the least serious form of arrhythmias. They can occur in healthy individuals and are often caused by factors such as caffeine intake, alcohol use, anxiety, or fatigue. Most people with extra beats do not require treatment, and the condition is usually identified through an ECG or a Holter monitor if symptoms warrant investigation.