[Mechanically-induced intraventricular block caused by a right-heart floating catheter--frequency and electrophysiologic findings].

During the course of 2,434 right heart catheterizations with 2,019 floating 3F Grandjean catheters and 415 5F Swan-Ganz catheters we observed 7 patients (0.3%) with catheter-induced infranodal conduction impairment: right bundle branch block (RBBB) in 3 patients, left anterior fascicular block (LAFB) and subsequent RBBB in 1 patient, and complete heart block in 3 patients with pre-existing left bundle branch block (LBBB). There was no apparent difference regarding the incidence of blocks between the two types of catheters. Three patients (one with LAFB + RBBB and two with LBBB) underwent electrophysiologic studies. All three patients exhibited a prolongation of the HV-interval due to coexisting pathologic changes of the right bundle. LBBB patterns disappeared during distal His bundle pacing in two patients, indicating a proximal site of block and suggesting incomplete involvement of the right bundle. Additional mechanical trauma, probably in this region, produced the blocks. Thus, use of balloon tipped or flexible catheters does not provide complete protection against transient lesions of the conduction system.