Myocytes, CardiacMyocardiumCells, CulturedHeartAnimals, NewbornCardiomegalyMyocardial ContractionRats, Sprague-DawleyHeart VentriclesRats, WistarCell DifferentiationApoptosisSignal TransductionCalciumMitochondria, HeartCell Culture TechniquesCell SurvivalMyocardial Reperfusion InjuryCardiotonic AgentsSarcomeresCell LineEmbryonic Stem CellsCell SizeGATA4 Transcription FactorMice, TransgenicCalcium Channels, L-TypeIsoproterenolMice, Inbred C57BLCell ProliferationHypertrophyConnexin 43Muscle CellsBlotting, WesternTime FactorsRNA, MessengerCalcium SignalingMicroscopy, ConfocalSarcoplasmic Reticulum Calcium-Transporting ATPasesReactive Oxygen SpeciesSarcolemmaCardiac MyosinsDisease Models, AnimalSodium-Calcium ExchangerReverse Transcriptase Polymerase Chain ReactionCardiomyopathiesImmunohistochemistryMyocardial IschemiaMyoblasts, CardiacPhosphorylationMuscle ProteinsVentricular MyosinsVentricular RemodelingAdrenergic beta-AgonistsCell Line, TumorGene ExpressionSarcoplasmic ReticulumGene Expression RegulationStem CellsHeart FailureInduced Pluripotent Stem CellsTransfectionDose-Response Relationship, DrugCardiomyopathy, DilatedCell HypoxiaCell ShapeAtrial Natriuretic FactorEnzyme InhibitorsExcitation Contraction CouplingUp-RegulationTissue EngineeringMyocardial InfarctionRegenerationPatch-Clamp TechniquesPhenylephrineEnzyme ActivationAdenoviridaeFibroblastsCytoprotectionMicroscopy, FluorescenceMice, KnockoutMembrane Potential, MitochondrialCell DeathHeart AtriaL-Lactate DehydrogenaseCell DivisionAction PotentialsCell MovementMyofibrilsAngiotensin IIEndothelin-1Caspase 3Models, BiologicalRyanodine Receptor Calcium Release ChannelArrhythmias, CardiacDiacetylOxidative StressModels, AnimalReceptors, Adrenergic, beta-1Hydrogen PeroxideMyosin Heavy Chains