What is characterized as an abnormal heart rhythm?

An abnormal heart rhythm is characterized by any deviation from normal sinus rhythm, which is the heart's natural and regular beating pattern initiated by the sinoatrial (SA) node. Normal sinus rhythm indicates a stable electrical conduction and regular timing of heartbeats, typically within a range of 60 to 100 beats per minute. When the heart rhythm deviates from this pattern, it becomes abnormal and may manifest as various arrhythmias, such as atrial fibrillation, bradycardia, or tachycardia.

While an accelerated heart rate can indicate an abnormal rhythm, it is not sufficient on its own to define it unless it deviates from the normal sinus pattern. Similarly, a consistent heartbeat might imply regularity but does not specifically pertain to the quality of the rhythm, as it could still be abnormal if it does not follow the normal sinus pattern. In essence, any variation from what is recognized as normal sinus rhythm qualifies as an abnormal heart rhythm.