Third-Degree Block
Atrial rate Regular; P to P is regular (if underlying rhythm sinus), 60 to 100 bpm, can be variable (eg atrial fibrillation)
Ventricular rate Regular; R to R is regular, ≤60 bpm (40 to 60 bpm fi junctional, 15 to 40 bpm if ventricular)
More P waves than QRS complexes (Complete A-V dissociation)
Unchanged unless aberrant conduction due to premature beat or increased rate