Cardiac dysrhythmias induced by infusion of local anesthetics into the lateral cerebral ventricle of cats.

The hypothesis that neurogenically mediated cardiac arrhythmias can be induced by the intracerebroventrical (ICV) infusion of local anesthetic solutions was tested in 11 chronically prepared, unmedicated cats. Test substances were bupivacaine (0.1%), lidocaine (0.4%), procaine (0.4 or 0.8%), or saline (pH 5.8). Cats received one or more of the test substances with two or more days between infusions. Four cats were also given bupivacaine intravenously at 1.1 and 1.4 mg/kg to help determine whether ECG changes after ICV injection of local anesthetic were due to direct cardiac action after systemic absorption. Total dose was 3.8-7.8 X the largest ICV dose (0.7 mg). No ventricular arrhythmias were observed after the ICV infusion of saline or with intravenous doses of bupivacaine as large as 1.4 mg/kg. Only one of six cats given lidocaine ICV developed sustained, severe ventricular arrhythmias. Five of seven cats given ICV procaine developed ventricular arrhythmias. All ten cats given ICV bupivacaine developed ventricular arrhythmias. It is concluded that local anesthetics can produce neurogenically mediated ventricular arrhythmias in cats and that, of the three local anesthetics tested, bupivacaine is the most potent and effective and lidocaine is the least potent and effective.