Cardiac Complexes, PrematureMyocytes, CardiacCardiac OutputHeartArrhythmias, CardiacCardiac Surgical ProceduresDeath, Sudden, CardiacCardiomegalyCardiac TamponadeCardiac Pacing, ArtificialHeart DiseasesMyocardiumCardiac CatheterizationMyocardial ContractionHeart ArrestHeart VentriclesMyoblasts, CardiacHeart FailureCardiomyopathiesCardiac MyosinsCardiac Imaging TechniquesElectrocardiographyCardiac GlycosidesHeart RateEchocardiographyCardiac Output, LowOut-of-Hospital Cardiac ArrestTime FactorsHemodynamicsMyocardial InfarctionCardiac VolumeVentricular RemodelingHeart TransplantationTroponin IVentricular Function, LeftHeart Defects, CongenitalStroke VolumeBlood PressureCardiac Resynchronization TherapyHeart Function TestsTroponin T