Sinus Tachycardia - EKG Reference Caliper Time Interval: ___ seconds RhythmRegular RateFast (> 100 bpm) P WaveNormal, may merge with T wave at very fast rates PR IntervalNormal (0.12-0.20 sec) QRSNormal (0.06-0.10 sec) NotesQT interval shortens with increasing heart rate Quick Links Sinus Atrial Junctional Ventricular Atrioventricular Pacemaker All