Observations of excessive delay and echoing of early premature responses in the dog heart suggest the existence of two parallel A-V conduction pathways.
This preclinical study provides foundational physiologic evidence for a dual A-V transmission system, explaining mechanisms of reciprocal rhythm and nodal paroxysmal tachycardia.
A study of the transmission of early premature contractions between atria and ventricles and in the retrograde direction in the dog heart suggests the existence of two parallel A-V conduction pathways communicating with each other over one or more branches. The evidence is based on the excessive delay of very early premature responses in traversing the node, suggesting that a slowly conducting pathway recovers earlier than the normal "fast" pathway; on the echoing back to the chamber of origin of early premature responses; and on ventricular electrograms of "abnormal" configuration obtained during early premature responses. These observations and the hypothesis to which they lead provide a natural explanation for reciprocal rhythm and nodal paroxysmal tachycardia.
Moe et al. (1956) studied A-V transmission / Arrhythmias. Early premature contractions (experimental observation) was evaluated on Transmission of early premature contractions between atria and ventricles. Observations of excessive delay and echoing of early premature responses in the dog heart suggest the existence of two parallel A-V conduction pathways.
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