Phase 3 and phase 4 bundle of branch block
Vitale, P.; De Cicco, D.; Vitale, N.; Nave, C.
Cardiologia 37(5): 363-367
1992
ISSN/ISBN: 0393-1978 PMID: 1423370 Document Number: 392920
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.