Baroreceptor-related dysrhythmias in piglets with selective autonomic denervation of the heart.

This study was carried out to determine whether selective cardiac autonomic denervation performed on neonatal swine would evoke dysrhythmias later in development. Piglets (n = 27; 5-10 days old) underwent unilateral stellate ganglion ablation, or right cardiac vagotomy, or sham surgery. Fifty to sixty days after denervation, acute experiments were performed to evaluate responses to baroreceptor activation. Of all animals who exhibited prolonged R-R intervals, only those with right stellate ganglion ablation had prolonged corrected QT intervals. Despite findings suggesting an arrhythmogenic state (predominance of left-sided cardiac innervation), dysrhythmias occurred in all animals with stellate ganglion ablation, regardless of laterality, but in few vagotomized or control animals. Our results suggest that partial sympathetic innervation may alter cardiac function so that dysrhythmias are more likely to occur during baroreceptor activation.