ElectrocardiographyArrhythmias, CardiacMyocytes, CardiacHeartHeart RateCardiac OutputDeath, Sudden, CardiacHeart Conduction SystemHeart DiseasesMyocardial InfarctionVectorcardiographyCardiac Surgical ProceduresHeart VentriclesElectrocardiography, AmbulatoryBrugada SyndromeSignal Processing, Computer-AssistedCardiac Pacing, ArtificialEchocardiographyTime FactorsPredictive Value of TestsCardiomegalyMyocardiumCardiac CatheterizationLong QT SyndromeProspective StudiesBundle-Branch BlockSensitivity and SpecificityCardiomyopathiesMyocardial ContractionChest PainTachycardiaVentricular FibrillationMyocardial IschemiaExercise TestTachycardia, VentricularHeart ArrestHeart FailureHeart BlockBlood PressureFollow-Up StudiesSyncopeTreatment OutcomeCoronary DiseaseDiagnosis, Computer-AssistedReproducibility of ResultsCardiac Complexes, PrematureTelemetryCardiac TamponadeRisk FactorsAnti-Arrhythmia AgentsHemodynamicsVentricular Function, LeftPhonocardiographyAutonomic Nervous SystemRetrospective StudiesBody Surface Potential MappingMonitoring, PhysiologicAtrial FibrillationVentricular Premature ComplexesStroke VolumeVentricular Dysfunction, LeftCreatine KinaseHeart AtriaBradycardiaArrhythmia, SinusCoronary AngiographyModels, CardiovascularPrognosisElectrophysiologic Techniques, CardiacHypertrophy, Left VentricularDogsTroponin ICardiomyopathy, HypertrophicCardiomyopathy, DilatedRisk AssessmentPericarditisVentricular FunctionAlgorithmsCardiac VolumeDeath, SuddenHeart Function TestsCardiac Resynchronization TherapyAngina PectorisPacemaker, ArtificialOut-of-Hospital Cardiac ArrestTroponin THeart Defects, CongenitalMyoblasts, CardiacAjmalineData Interpretation, StatisticalAtrioventricular BlockVentricular RemodelingCardiac MyosinsCardiac Imaging TechniquesHeart TransplantationPericardiumObserver VariationCardiac GlycosidesClinical Enzyme TestsHeart Auscultation