Sinus rhythm
Sinus rhythm is the heart's normal rhythm, driven by its natural pacemaker, the sinus node, in the upper right chamber. When your heartbeat originates there and follows its usual path, an ECG shows the regular, expected pattern.
Sinus rhythm is the baseline against which other rhythms are compared, so seeing it is generally reassuring. It tells the clinician that your heart's electrical signal is starting in the right place and traveling as it should.
When the rhythm deviates from normal sinus rhythm, appearing irregular or originating from elsewhere, it can indicate an arrhythmia such as atrial fibrillation. Some of these patterns are minor while others matter more, so any tracing described as abnormal or irregular is best interpreted by a clinician.
Even within sinus rhythm, the rate can be faster (sinus tachycardia) or slower (sinus bradycardia) than average, which is often normal but occasionally warrants a closer look with symptoms.
A regular sinus rhythm at a normal rate is the typical healthy pattern, but rhythm findings should always be confirmed and interpreted by a clinician reading the full ECG. Automated rhythm labels can be imperfect and are not a diagnosis.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.