Intraventricular conduction disturbances in flying personnel: incomplete right bundle branch block

We studied the evolving characteristics, as well as the qualification criteria, applied to 261 fliers with incomplete right bundle branch block (IRBBB), detected in a presumable healthy population of 7,685 males engaged in civilian flying activities (prevalence 3.4%). In 136 cases, the IRBBB was detected in the first electrocardiogram. The highest prevalence was observed between 20 and 29 years of age. The IRBBB was permanent in 66 cases and transitory in the remaining 195. The electrical axis shifted to the left in 94 cases. Twelve cases (4.6%) evolved to complete RBBB. The IRBBB pattern implies many different clinical conditions. Flying fitness certification depends upon the cause of the IRBBB. Those due to conduction disturbance with no underlying pathology may qualified. IRBBB associated with other conduction disturbance deserves further study for possible restricted qualification.