Regulation of ventricular contraction. Influence of cardiac sympathetic and vagal nerve stimulation on atrial and ventricular dynamics.

摘要: At constant heart rates, efferent stimulation of the vagus nerve and left stellate ganglion revealed following: 1. Vagal exerts a profound depressant effect on strength atrial contraction can thereby influence ventricular filling stroke work; it elevates mean pressure at any given level work. This occurs under experimental conditions wherein vagal used does not produce an alteration in performance characteristics ventricle. The effects are blocked by atropine. 2. Stellate or norepinephrine infusion augments thus contribution to filling. augmented takes place shorter period time. 3. increases external work power produced ventricle from end-diastolic fiber length.4. There is family curves representing relation between length work, as well work.5. When taken together with well-known sympathetic parasympathetic rate, above data believed comprise reasonably comprehensive description means available central nervous system for directly inducing acute changes activity heart.