Sinus rhythm (a.k.a. normal sinus rhythm ... Note that ectopic atrial rhythms can have a P wave before each QRS complex, however the P wave is not upright in lead II since it originates in ...

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. A sinus morphology is an upright P wave in lead II and ...

Less commonly, sinus arrhythmia may indicate an underlying medical problem, like heart disease or heart block. The heart's normal sinus rhythm is created ... throughout. A QRS complex will follow ...