The effect of therapeutic doses of lidocaine hydrochloride on the effective refractory period of the right ventricle in man.

The effect of lidocaine on the effective refractory period of the right ventricle (EVRP) was measured in 10 patients using the extra stimulus technique of progressive introduction of premature stimuli until a response could not be elicited. In four patients lidocaine produced a significant decrease in the EVRP, in a further four patients there was no change, and in the remaining two patients lidocaine produced a significant increase in the EVRP. The effect of the drug on the EVRP could not be correlated with the serum potassium levels. The reasons for the variable effect of lidocaine are attributed to the different action of lidocaine on different components of conduction within the ventricle.