Functional longitudinal dissociation of the nodal-His bundle conduction system in the electrophysiological study of a "short PR with narrow QRS"
Baudouy, M.; Camous, J.P.; Varenne, A.; Guarino, L.; Patouraux, G.; Guiran, J.B.
Archives des Maladies du Coeur et des Vaisseaux 73(12): 1407-1414
1980
ISSN/ISBN: 0003-9683 PMID: 6779728 Document Number: 166447
Endocavitary electrophysiological investigation of a patient with a short PR interval/narrow QRS syndrome revealed the possibility of functional longitudinal dissociation of the nodo-Hisian pathway. The patient was a 35 yr old woman with a history of palpitations. No attacks of tachycardia were recorded on repeated ECG recordings. Premature right atrial stimulation progressively induced dissociation of the His potential into 2 components and deformation of the ventriculogram consisting of slurring of the upstroke suggestive of a .delta. wave of ventricular preexcitation and slight delay in left ventricular activation. At sufficiently short coupling intervals the 2nd His potential and the initial slurring of the QRS disappeared simultaneously although atrioventricular conduction was maintained. The significance of the splitting of this His potential is discussed; a 1st degree intra-Hisian block with recording of the depolarization of the right bundle branch was eliminated from the onset. An accessory pathway by Mahaim Hiso-ventricular fibers was not excluded but this is probably not the cause of the 2nd potential. After discussing the possibility of a nodo-ventricular pathway, functional longitudinal nodo-Hisian dissociation seemed the most likely cause of this phenomenon. All cases of ventricular aberration should be studied in the light of this hypothesis.