Myocytes, CardiacAnimals, NewbornMyocardiumCells, CulturedHeartCardiomegalyRats, Sprague-DawleyRats, WistarMyocardial ContractionHeart VentriclesHypertrophyAtrial Natriuretic FactorPhenylephrineIsoproterenolCalciumAngiotensin IIRNA, MessengerEndothelin-1Cell SizeProtein Kinase CSignal TransductionStress, MechanicalApoptosisDose-Response Relationship, DrugEnzyme ActivationGene Expression RegulationTransfectionTranscription, GeneticGene ExpressionPromoter Regions, GeneticSarcomeresMuscle CellsAdrenergic beta-AgonistsSarcolemmaSodium-Calcium ExchangerTime FactorsFibroblastsMitochondria, HeartReceptors, AngiotensinCalcium Channels, L-TypeEnzyme InhibitorsPatch-Clamp TechniquesCalcium SignalingReceptors, Adrenergic, betaMembrane PotentialsPhosphorylationCardiotonic AgentsSarcoplasmic ReticulumCalcium-Calmodulin-Dependent Protein KinasesMitogen-Activated Protein KinasesBlotting, WesternArrhythmias, CardiacCardiac OutputAction PotentialsModels, CardiovascularSarcoplasmic Reticulum Calcium-Transporting ATPasesAdrenergic alpha-AgonistsMuscle ProteinsReceptors, Adrenergic, alpha-1Potassium ChannelsVentricular FunctionTroponin ICaveolin 3CaffeineHEPESCyclic Nucleotide Phosphodiesterases, Type 2Electric StimulationRats, Inbred StrainsElectrophysiologyCyclic AMP-Dependent Protein KinasesCalcium ChannelsMicroscopy, ConfocalRyanodine Receptor Calcium Release ChannelMyocardial IschemiaSodium-Potassium-Exchanging ATPaseSodium ChannelsMuscle Fibers, SkeletalHeart AtriaCell HypoxiaKineticsFluorescent DyesBenzophenanthridinesCardiac Surgical ProceduresAdenosine TriphosphateCyclic AMPAdenoviridaeGuinea PigsCardiomyopathiesElectric ConductivityDeath, Sudden, CardiacCalcium-Transporting ATPasesPhosphodiesterase InhibitorsCell DivisionSodiumHeart FailureIsoenzymesOuabainCalcium-Binding ProteinsHeart TransplantationActin Cytoskeleton