HeartHeart RateMyocardiumHeart FailureMyocytes, CardiacFetal HeartHeart DiseasesHeart TransplantationMyocardial ContractionHeart Defects, CongenitalHeart ValvesMyocardial Reperfusion InjuryHeart AtriaMice, Inbred C57BLCardiomegalyMyocardial IschemiaPerfusionMice, TransgenicCardiotonic AgentsHeart Function TestsMyocardial InfarctionMice, KnockoutCardiomyopathiesHeart BlockVentricular Function, LeftIschemic Preconditioning, MyocardialTime FactorsHemodynamicsDisease Models, AnimalHeart Arrest, InducedIsoproterenolCalciumCardiomyopathy, DilatedVentricular RemodelingEchocardiographyMyocarditisHeart VentriclesMitochondria, HeartVentricular MyosinsVentricular PressureHeart SeptumMyocardial ReperfusionRNA, MessengerEndocardiumSarcoplasmic Reticulum Calcium-Transporting ATPasesFibrosisCoronary DiseaseAdrenergic beta-AgonistsModels, CardiovascularConnexin 43Cells, CulturedVentricular Dysfunction, LeftModels, AnimalOxygen ConsumptionHeterocyclic Compounds, 3-RingExcitation Contraction CouplingStroke VolumeTroponin ISarcoplasmic ReticulumVentricular DysfunctionSignal TransductionGene Expression Regulation, DevelopmentalMyosin Heavy ChainsMyofibrilsMice, Inbred StrainsCardiac Output, LowAction PotentialsGene ExpressionHeart Conduction SystemAnimals, NewbornVentricular FunctionVoltage-Sensitive Dye ImagingSinoatrial NodeTroponin TAtrioventricular NodeHeart, ArtificialHeart Failure, SystolicMuscle ProteinsCardiac Pacing, ArtificialSodium-Calcium ExchangerReceptors, Adrenergic, betaGene Expression RegulationHeart InjuriesEnergy MetabolismRats, Sprague-DawleyHeart Rate, FetalRheumatic Heart DiseaseCardiac MyosinsProtein IsoformsAdenosine TriphosphateBlotting, WesternHeart ArrestRisk FactorsCreatine KinaseAgingHeart Valve ProsthesisArrhythmias, CardiacSarcomeresImmunohistochemistrySystole