Reversible blockade of myelinated and non-myelinated cardiac afferents in cats by instillation of procaine into the pericardium.

Pericardial local anaesthesia was instituted in 33 chloralosed cats through catheters implanted into the pericardium. The activity of 1531 single fibres teased from either vagus in the neck was identified and classified according to source. Random testing with 2% procaine instilled into the pericardium revealed that only cardiac afferents could be blocked.