ElectrocardiographyArrhythmias, CardiacMyocytes, CardiacHeartCardiac OutputHeart RateDeath, Sudden, CardiacHeart Conduction SystemHeart DiseasesMyocardial InfarctionVectorcardiographyDevice ApprovalCardiac Surgical ProceduresElectrocardiography, AmbulatoryCardiac Pacing, ArtificialHeart VentriclesSignal Processing, Computer-AssistedEchocardiographyBrugada SyndromeTime FactorsEquipment DesignCardiac CatheterizationCardiomegalyMyocardiumLong QT SyndromeProspective StudiesPredictive Value of TestsBundle-Branch BlockCardiomyopathiesHeart FailureVentricular FibrillationMyocardial ContractionTachycardiaTelemetryTreatment OutcomeMyocardial IschemiaChest PainTachycardia, VentricularHeart ArrestHeart BlockExercise TestBlood PressureFollow-Up StudiesSyncopeSensitivity and SpecificityEquipment SafetyHemodynamicsCardiac TamponadeIntrauterine DevicesCardiac Complexes, PrematureCoronary DiseaseVentricular Function, LeftMonitoring, PhysiologicAnti-Arrhythmia AgentsPacemaker, ArtificialPhonocardiographyAutonomic Nervous SystemBody Surface Potential MappingAtrial FibrillationStroke VolumeRisk FactorsDiagnosis, Computer-AssistedVentricular Dysfunction, LeftRetrospective StudiesDevice RemovalHeart AtriaVentricular Premature ComplexesBradycardiaArrhythmia, SinusCoronary AngiographyCreatine KinaseCardiomyopathy, DilatedElectrophysiologic Techniques, CardiacModels, CardiovascularCardiac Resynchronization TherapyReproducibility of ResultsEquipment and SuppliesHypertrophy, Left VentricularDogsCardiomyopathy, HypertrophicTroponin IDeath, SuddenCardiac VolumePericarditisVentricular FunctionHeart Function TestsDefibrillators, ImplantableRisk AssessmentPrognosisOut-of-Hospital Cardiac ArrestHeart TransplantationAngina PectorisCardiac Resynchronization Therapy DevicesHeart Defects, CongenitalTroponin TAtrioventricular BlockVentricular RemodelingMyoblasts, CardiacAjmalineSeptal Occluder Device