The effect of calcium and sodium ion on the frequency-force relationship in cardiac muscle.
D000818:Animals; D016275:Atrial Function; D002118:Calcium / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000502:physiology; D011817:Rabbits; D012964:Sodium / Q000494:pharmacology*; D016276:Ventricular Function
D012964:Sodium; D002118:Calcium