Direct cause of this is improper work of the Lower Esophageal Sphincter valve (LES).
A good overview in:
Mapping of esophagus and it's muscles in a stomach system:
Heat--->Dampness (stomach)--->Heat (esophagus)--->Wind (muscles): No harmonization
to address all possible problems altogether through No point, or more generally:
Heat--->Dampness --->Wind (muscles in stomach system): No harmonization
right hand, chronic case.
Another approach aims at energy ban on the abnormal path for acid upward, where chain of energies describe this:
Heat-Dampness (stomach)--->Burn (stomach cardia)--->Heat (esophagus)--->Wind (throat): No (termination) tone up