title: [Phase 3 and phase 4 bundle of branch block].
abstract: Intermittent left bundle branch blocks are present in the ECGs of 1 patient with mitral valve disease. By occurring either after short or long cycles they represent respectively phase 3 and phase 4 blocks. Such mechanisms emphasize the relationship between automatism and conduction. The occurrence of block and of normal conduction during cycles of the same length, its correlation with the conduction of the previous cycle, demonstrate the presence of a functional linking between successive impulses. This linking may occur every time a potential or active macroreentry circuit exist. In our case the circuit is formed by the 2 bundle branches which join distally in the ventricular septum.
authors.affiliation: Cattedra di Cardiologia, Università degli Studi, Napoli.
authors.forename: P
authors.initials: P
authors.lastname: Vitale
authors.forename: D
authors.initials: D
authors.lastname: De Cicco
authors.forename: N
authors.initials: N
authors.lastname: Vitale
authors.forename: C
authors.initials: C
authors.lastname: Nave
mesh_terms: D002037:Bundle-Branch Block / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008875:Middle Aged
vernacular_title: Blocco di branca in fase 3 ed in fase 4 e linking del blocco in fase 3: descrizione di un caso.