Dynamic vagal control of atrial-ventricular condition: theoretical and experimental studies.

摘要: The dynamic effects of vagal stimulation on atrial-ventricular conduction were studied with paced canine hearts under β-adrenergic blockade. An analog/hybrid computer was used to precisely control the intensity and timing a stimulus burst given cervical vagosympathetic trunk, measure response. On-line digital techniques generate composite “vagal effect curve” which is representation nerve-ending process dynamics. It clearly seen that magnitude AV response critically dependent upon time in cardiac cycle at given. A functionally isomorphic mathematical model, consisting independent but coupled nodal vagal-acetylcholine subsystems, derived simulate predict specific characteristics variety curves. These predictions subsequently confirmed experimental conditions. For example, peak amplitude an curve increases increasing precise nonlinear fashion predicted by model. further concluded certain changes shape curves are more likely related state node itself, rather than processes govern release, diffusion, inactivation acetylcholine. also demonstrated for course need not exactly coincide computed ACh concentration affected cell membrane, as has been assumed previously SA node.