Advanced A-V block with apparent A-V junctional escape complexes because of dual A-V nodal pathways.
We report a patient with second degree A-V block in whom several sinus impulses were conducted over the slow A-V nodal pathway, resulting in P-R intervals so prolonged to suggest a diagnosis of intermittent advanced A-V block with A-V junctional escape complexes. However, the "escape" cycles were markedly irregular, and moreover, "escape" complexes often occurred with R-R cycles shorter than those ended by conducted sinus beats. These observations suggested that no escape mechanism was present. The marked variability of P-R intervals was a manifestation of dual A-V nodal pathways: short P-R intervals expressed conduction over the fast pathway, whereas long P-R intervals corresponded to sinus impulses conducted over the slow pathway.
Luzza
F
F
Dipartimento Clinico-Sperimentale di Medicina e Farmacologia, Cattedra di Cardiologia, Università di Messina, Via Terranova 9, 98122 Messina, Italy.
Carerj
S
S
Oreto
G
G
D000368:Aged; D001283:Atrioventricular Node / Q000503:physiopathology*; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans