[Basic study of the contractile force of the myocardium].
D000200:Action Potentials; D000818:Animals; D001001:Anura; D004285:Dogs; D004558:Electric Stimulation; D004562:Electrocardiography; D004566:Electrodes; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D009119:Muscle Contraction; D009991:Oscillometry; D011312:Pressure; D012666:Semiconductors; D014159:Transducers