2022 Volume 42 Issue 1 Pages 14-25
An 83-year-old man presented 5 types of QRS complexes during 30 years of observation. At his first visit at age 53, his electrocardiogram（ECG）showed sinus rhythm and QRS complex was complete right bundle branch block pattern（CRBBBp）with QRS axis＋15˚［C15］. At the age of 74, QRS complex remained CRBBBp, but the QRS axis shifted rightward to＋60˚［C60］. At the age of 76, atrial fibrillation was recorded for the first time, but QRS complex still showed［C60］. At the age of 78,［C15］was intermittently exhibited when preceding RR interval was above 1.01sec. At the age of 79, IRBBBp-QRS complex was intermittently exhibited when preceding RR interval was above 0.98sec, but the QRS axis remained unchanged at＋60˚［I60］regardless of the preceding RR interval. At the age of 80, 3 types of QRS complexes of［C60］, ［C15］, and IRBBBp with QRS axis＋15˚［I15］were observed. At the age of 83, in addition to［I60］, normal narrow QRS with axis＋70˚［N70］was exhibited when preceding RR interval was in the range of 0.44-0.48sec. Thus, QRS complexes remained right bundle branch block pattern, but QRS duration and QRS axis changed at different critical preceding RR intervals. These phenomena cannot be explained by the right bundle branch block only. However, they might be explained by the hypothesis of a triple pathway derived from the longitudinal dissociation within the His bundle.
