Myocytes, CardiacMyocardiumHeartStress, MechanicalHeart VentriclesMyocardial ContractionCells, CulturedCardiomegalyCalciumRats, Sprague-DawleyAnimals, NewbornMuscle CellsCardiac OutputArrhythmias, CardiacCalcium Channels, L-TypeIsoproterenolVentricular FunctionSodium-Calcium ExchangerRats, WistarSarcolemmaMechanical ProcessesTime FactorsPatch-Clamp TechniquesGuinea PigsCalcium SignalingCardiac Surgical ProceduresSarcomeresBiomechanical PhenomenaHeart AtriaSarcoplasmic ReticulumDeath, Sudden, CardiacAction PotentialsMembrane PotentialsModels, CardiovascularAdrenergic beta-AgonistsCell SizeMitochondria, HeartCardiomyopathiesHeart FailureMechanical PhenomenaSignal TransductionCardiac Pacing, ArtificialMuscle ProteinsReceptors, Adrenergic, betaPotassium ChannelsHeart DiseasesSarcoplasmic Reticulum Calcium-Transporting ATPasesCardiotonic AgentsDogsRabbitsRNA, MessengerRyanodine Receptor Calcium Release ChannelElectrophysiologyAtrial Natriuretic FactorMechanotransduction, CellularCalcium ChannelsMyocardial IschemiaGATA4 Transcription FactorPhenylephrineElasticityMyosin Heavy ChainsCaveolin 3Respiration, ArtificialTroponin IReceptors, Adrenergic, beta-1Disease Models, AnimalMicroscopy, ConfocalVentricular RemodelingMice, TransgenicCardiac TamponadeMyocardial Reperfusion InjuryCardiac MyosinsCaffeineMyocardial InfarctionEndothelin-1PhosphorylationEnzyme InhibitorsMice, KnockoutCardiomyopathy, DilatedPhysical StimulationSodium ChannelsDose-Response Relationship, DrugMyoblasts, CardiacGene Expression RegulationCardiac CatheterizationMyofibrilsModels, BiologicalHeart RateElectrocardiographyExcitation Contraction CouplingMice, Inbred C57BLHypertrophyHemodynamicsVentricular Function, LeftEchocardiographyMuscle Fibers, SkeletalCyclic AMP-Dependent Protein KinasesKineticsCardiac Output, LowProtein Kinase C