These lines are comprised of three main parts: In normal sinus rhythm, the P-P interval (the time between consecutive P waves ...

6,11 Heart rates ≥30 beats/min are considered normal in highly trained athletes ... Sinus rhythm resumes with increased heart rates during exercise. In an ectopic atrial rhythm, P waves are present ...

There is no associated P wave, although an independent normal ... sinus depolarization would suppress it 2,3. Figure 2: An ECG obtained from a beagle dog 21 days later, showing six rhythm strips ...