Any process that stops, prevents or reduces the frequency, rate or extent of membrane depolarization during a cardiac muscle cell action potential.
Synonyms:
exact_synonym:
down regulation of membrane depolarization during cardiac muscle cell action potential; down-regulation of membrane depolarization during of cardiac muscle cell action potential; downregulation of membrane depolarization during cardiac muscle cell action potential
narrow_synonym:
inhibition of membrane depolarization during cardiac muscle cell action potential