Atrial Fibrillation - EKG Reference Caliper Time Interval: ___ seconds RhythmIrregular RateVery fast (> 350 bpm) for Atrial, but ventricular rate may be slow, normal or fast P WaveAbsent - erratic waves are present PR IntervalAbsent QRSNormal but may be widened if there are conduction delays Notes Quick Links Sinus Atrial Junctional Ventricular Atrioventricular Pacemaker All