Deterministic model of the canine atrio-ventricular node as a periodically perturbed, biological oscillator

Abstract

The atrio-ventricular (AV) node may be regarded as a periodically perturbed, biologicaL oscillator. In that case the ventricular response to atrial excitation can be described by a latency-phase curve. The phase is approximated by the time between a QRS-complex and an atrial stimulus S (R-S interval), the latency by the time between this stimulus and the following QRS-complex (S-R interval). This hypothesis was checked against results obtained in six anesthetized, pharmacologically denervated dogs. An exponential relationship between S-R and R-S intervals was obtained from normally conducted, premature atrial stimuli. This latency-phase relationship resulted in a deterministic model of the AV conduction system. Step increases and decreases in atrial stimulation rate yielded S-R intervals in the dog that corresponded to the intervals predicted by the model. These preliminary results support the hypothesis that not only the canine, but also the human AV node may function as a periodically perturbed, biological oscillator.