Myocardial ContractionMuscle ContractionHeartMyocytes, CardiacMyocardiumExcitation Contraction CouplingCalciumSarcomeresHeart VentriclesIsometric ContractionVentricular PressureDogsVentricular FunctionModels, CardiovascularIsoproterenolHeart RateSarcoplasmic ReticulumCoronary CirculationRabbitsUterine ContractionRats, Sprague-DawleyCardiac OutputMuscle, SmoothArrhythmias, CardiacCardiac Surgical ProceduresDeath, Sudden, CardiacElectric StimulationMuscle, SkeletalGuinea PigsCardiac Pacing, ArtificialVasoconstrictionTime FactorsCardiomegalyIsotonic ContractionCardiac TamponadeHeart DiseasesCardiac CatheterizationMuscle, Smooth, VascularMuscle RelaxationDose-Response Relationship, DrugNorepinephrineHeart ArrestMuscle FatigueElectromyographyRats, WistarHeart FailureElectrocardiographyMusclesPotassium ChlorideCardiac MyosinsCardiomyopathiesVasoconstrictor AgentsPhenylephrineBlood PressureHemodynamicsGastrointestinal MotilityEchocardiographyMyoblasts, CardiacTracheaAtropineVentricular Function, LeftAcetylcholineTroponin ICardiac GlycosidesCardiac Imaging TechniquesPeristalsisUrinary BladderCells, CulturedCardiac Output, LowMyosinsAorta, ThoracicNifedipineCardiac VolumeMyocardial InfarctionVentricular RemodelingAction PotentialsOut-of-Hospital Cardiac ArrestMyosin Light ChainsCardiotonic AgentsHeart TransplantationCalcium Channel BlockersHeart AtriaMyofibrilsPotassiumCarbacholStroke VolumeVas DeferensPapillary MusclesMuscle TonusMuscle ProteinsHeart Conduction SystemIleumCaffeineTroponin TMuscle Fibers, SkeletalHeart Defects, CongenitalEnzyme InhibitorsVentricular Dysfunction, LeftDisease Models, Animalrho-Associated Kinases