How is a cardiac arrhythmia defined?

A cardiac arrhythmia is defined as any cardiac rhythm other than the normal sinus rhythm. Normal sinus rhythm is characterized by a consistent heart rate, typically between 60 to 100 beats per minute, that originates from the sinoatrial node, the heart's natural pacemaker. When the rhythm deviates from this standard—whether it is too fast, too slow, or irregular—it is classified as an arrhythmia. This broad definition encompasses various types of arrhythmias, including bradycardia (slow heart rate), tachycardia (fast heart rate), and various types of irregularities that impact heart functionality.

The other definitions provided do not accurately capture the full scope of what constitutes an arrhythmia. A rhythm that is regular and consistent does not necessarily indicate a normal or healthy heart rhythm, as it could still be abnormal. A heart rate of less than 60 beats per minute specifically refers to bradycardia, which is a type of arrhythmia but does not encompass the full range of possibilities. Lastly, a non-ventricular paced rhythm is a specific type of rhythm and does not encompass the broader category of abnormal rhythms experienced in arrhythmias. Thus, identifying any cardiac rhythm outside normal sinus rhythm as