Normal Sinus Rhythm
Normal electrical conduction starting in the sinoatrial node.
Criteria
- Rate 60 to 100 bpm
- Regular rhythm
- Upright P in II, III and aVF
- PR interval 120 to 200 ms
- QRS under 120 ms
On the tracing
- Normal axis
- Isoelectric ST segments
- T waves in the same direction as the QRS