HeartMyocytes, CardiacHeart RateCross CirculationMyocardial ContractionCardiac OutputArrhythmias, CardiacMyocardiumAmrinoneHeart DiseasesElectrocardiographyMinoxidilVentricular Function, LeftBradycardiaCardiomegalyBlood PressureHeart VentriclesHemodynamicsEchocardiographyDogsCardiomyopathiesHeart FailureCardiac Surgical ProceduresDose-Response Relationship, DrugDeath, Sudden, CardiacCoronary CirculationVentricular PressurePapillary MusclesVentricular RemodelingCardiotonic AgentsGuinea PigsHeart AtriaTime FactorsPerfusionVentricular FunctionHeart Conduction SystemMyocardial InfarctionHypertrophy, Left VentricularRats, WistarDepression, ChemicalRats, Sprague-DawleyStroke VolumePropranololMyocardial IschemiaCardiac TamponadeCardiac Pacing, ArtificialOxygen ConsumptionAtropineAdrenergic beta-AntagonistsIsoproterenolCardiac CatheterizationDisease Models, AnimalHeart ArrestNorepinephrineDoxorubicinAntihypertensive AgentsMyoblasts, CardiacHypertensionCardiac MyosinsCardiac Imaging TechniquesCardiac GlycosidesCardiac Output, LowOut-of-Hospital Cardiac ArrestDouble-Blind MethodCardiac VolumeHeart TransplantationTroponin IHeart Defects, CongenitalCardiac Resynchronization TherapyHeart Function TestsTroponin TCardiopulmonary ResuscitationHeart NeoplasmsCardiac Care FacilitiesCardiomyopathy, DilatedVentricular Dysfunction, LeftTreatment OutcomeCardiac ElectrophysiologyModels, CardiovascularFibrosisFetal HeartCalciumProspective StudiesCells, CulturedHeart InjuriesCardiopulmonary BypassTroponinFollow-Up StudiesMyocarditisMice, TransgenicSarcomeresAtrial Natriuretic FactorMuscle ProteinsRetrospective StudiesRisk FactorsMitochondria, HeartHeart ValvesPericardiumPredictive Value of TestsPacemaker, Artificial