Sinus rhythm (a.k.a. normal sinus rhythm) refers to the normal heart beat originating from the sinoatrial node. This is manifested as an upright P wave in lead II of the ECG. Sinus bradycardia ...

To understand the difference between normal sinus rhythm and sinus arrhythmia, it's best to start by exploring the role of an electrocardiogram (ECG or EKG) in diagnosing such rhythms. During an ...

This results in an upright P wave in lead II on the ECG. If there is a P wave before every QRS complex, and it has a sinus morphology, then normal sinus rhythm, or NSR, is said to be present.