Compensating conduction times as a mechanism of alternating reentry tachycardia: Computer modelling experiments

Abstract

This article concerns a currently reported hypothesis explaining the alternations of conduction time during intra atrioventricular (AV) nodal reentrant tachycardia (AVNRT). This hypothesis supposes simple mutual influence of sequences of intranodal conduction during reentry tachycardia that use the same circuit in different tachycardia cycles. It has been suggested that delayed conduction prolongs the recovery time of the circuit, thus making it possible to transmit the excitation wave with a faster speed in the next tachycardia loop; this less delayed loop shortens the recovery interval of the pathway and results in subsequently delayed conduction of the following tachycardia cycle. A computer model simulating intra-AV nodal reentranl conduction was used to imitate and prove this hypotheses. The results are negative, showing that the suggested mechanism is too simplistic and that either the pathophysiologic background of the AVNRT cycle length oscillations must be different or additional phenomena must be considered to improve the hypothesis.