Left stellectomy and denervation supersensitivity in conscious dogs

The possibility that denervation Supersensitivity might result from left Stellectomy was investigated because of its potential clinical implications. The study was conducted in 12 conscious dogs by injecting norepinephrine as a bolus dose or as an infusion before and 2 to 4 weeks after left Stellectomy. The variables analyzed were the first derivative of left ventricular pressure (dP/dt max) and the number of premature ventricular complexes. Under control conditions dP/dt max was unaffected by left Stellectomy (3,572 ± 280 versus 3,549 ± 235 mm Hg/s). Bolus injections and infusions produced the same results and showed no difference in the increases in dP/dt max produced by norepinephrine observed before and after left Stellectomy. For example, with the largest dose of norepinephrine, 1.25 μg/kg, the changes from the control value were 4,533 ± 269 and 5,032 ± 668 mm Hg/s, respectively (difference not significant). The number of premature ventricular complexes resulting from the two largest doses of norepinephrine was significantly decreased after left Stellectomy (85 ±12 versus 46 ± 14, p <0.05), and ventricular tachycardia, which occurred in three dogs under control conditions, was never observed after left Stellectomy. This study reveals another aspect of the antiarrhythmic effect of left Stellectomy and demonstrates that it does not produce denervation Supersensitivity.