The Duration and Intensity of High Frequency Alternating Current Influences the Degree and Recovery of Nerve Conduction Block

Objective
: The purpose of this paper is to investigate the persistence of nerve blockade beyond the duration of applying high frequency alternating current (HFAC) to thinly myelinated and non-myelinated fibers, also termed a “carry-over effect”.
Methods
: In this study, we used electrically-evoked compound action potentials from isolated rat vagus nerves to assess the influence of 5 kHz HFAC amplitude and duration on the degree of the carry-over effect. Current amplitudes from 1–10 mA and 5 kHz durations from 10–120 seconds were tested.
Results
: By testing 20 different combinations of 5 kHz amplitude and duration, we found a significant interaction between 5 kHz amplitude and duration on influencing the carry-over effect.
Conclusion
: The degree of carry-over effect was dependent on 5 kHz amplitude, as well as duration.
Significance
: Utilizing the carry-over effect may be useful in designing energy efficient nerve blocking algorithms for the treatment of diseases influenced by nerve activity.