DigoxinMyocytes, CardiacCardiac OutputCardiac GlycosidesDigitoxinCardiotonic AgentsHeartArrhythmias, CardiacCardenolidesCardiac Surgical ProceduresDeath, Sudden, CardiacHeart FailureMedigoxinMyocardiumHeart DiseasesEleutherococcusMyocardial ContractionCardiac Pacing, ArtificialAnti-Arrhythmia AgentsCardiomegalyCardiac TamponadeCardiac CatheterizationDigitalis GlycosidesHeart ArrestElectrocardiographyHeart VentriclesTime FactorsDrug InteractionsHeart RateNeriumOuabainCardiac Output, LowHemodynamicsMyoblasts, CardiacCardiomyopathiesEchocardiographyDogsRadioimmunoassayCardiac MyosinsVentricular Function, LeftCardiac Imaging TechniquesSodium-Potassium-Exchanging ATPaseQuinidineP-GlycoproteinHeart TransplantationStroke VolumeSaponins