title: [Refractory, excitatory, and over-excitatory periods].
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000200:Action Potentials; D000368:Aged; D000818:Animals; D004285:Dogs; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000209:etiology
chemical_list: D000109:Acetylcholine