Co-existing tachycardia and bradycardia dependent incomplete and complete right bundle branch block: evidence for diffuse conduction system involvement

A case of co-existing tachycardia and bradycardia dependent incomplete and complete right bundle branch block (BBB) is reported. The degree of BBB was related to the duration of the preceding cycle length. In addition, more diffuse conduction system disease was suggested by evidence of sino-atrial and His-Purkinje conduction abnormalities.