Myocytes, CardiacMyocardiumCardiomegalyHeartMyocardial ContractionHeart VentriclesMuscle CellsCells, CulturedCardiac OutputCardiomyopathiesRats, Sprague-DawleyCell SizeArrhythmias, CardiacSarcomeresAnimals, NewbornVentricular RemodelingMyosin Heavy ChainsCardiac Surgical ProceduresHeart FailureDeath, Sudden, CardiacCalciumIsoproterenolHeart DiseasesHypertrophyGATA4 Transcription FactorMice, TransgenicSignal TransductionModels, CardiovascularTime FactorsVentricular Function, LeftMEF2 Transcription FactorsAtrial Natriuretic FactorVentricular FunctionApoptosisEchocardiographyMice, KnockoutMyogenic Regulatory FactorsDisease Models, AnimalCardiac Pacing, ArtificialMyocardial InfarctionMyocarditisHemodynamicsMyocardial IschemiaCardiotonic AgentsFibrosisCardiomyopathy, DilatedCalcium SignalingPhenylephrineMice, Inbred C57BLSarcoplasmic Reticulum Calcium-Transporting ATPasesCardiac TamponadeMitochondria, HeartSarcolemmaMuscle ProteinsCalcium Channels, L-TypeRats, WistarGene Expression RegulationReceptors, Adrenergic, betaReceptors, Adrenergic, beta-1Excitation Contraction CouplingAdrenergic beta-AgonistsMyofibrilsCardiac CatheterizationHypertrophy, Left VentricularRNA, MessengerVentricular Dysfunction, LeftMyocardial Reperfusion InjuryCardiac MyosinsPhosphorylationDogsHeart ArrestSodium-Calcium ExchangerReoviridae InfectionsA Kinase Anchor ProteinsSarcoplasmic ReticulumAngiotensin IIEnzyme InhibitorsEndothelin-1Caveolin 3ElectrocardiographyAdenoviridaeOrgan SizeCell EnlargementBlood Physiological PhenomenaMyoblasts, CardiacHeart RateBlotting, WesternCalcium-Binding ProteinsGene ExpressionTroponin IBlood PressureCardiac Imaging TechniquesEnzyme ActivationCaspase 3Cardiac GlycosidesHeart TransplantationAction PotentialsCell DifferentiationSodium-Potassium-Exchanging ATPaseCell Survival