The first ECG strip below shows a P wave with sinus morphology, thus normal sinus rhythm. If the P wave has a morphology different from the typical sinus morphology, it is termed ectopic ...

Less commonly, sinus arrhythmia may indicate an underlying medical problem, like heart disease or heart block. The heart's normal sinus rhythm is created by electrical signals that spread ...

Ectopic, originating outside of the SA node, and thus, the P wave morphology would be different from the normal sinus P wave morphology ... as seen in this strip above. If a PAC occurs when ...