Arrhythmias, CardiacElectrocardiographyArrhythmia, SinusMyocytes, CardiacHeartDeath, Sudden, CardiacHeart Conduction SystemHeart RateTachycardia, VentricularAnti-Arrhythmia AgentsElectrocardiography, AmbulatoryVentricular FibrillationHeart VentriclesCardiac OutputMyocardial InfarctionLong QT SyndromeCardiac Pacing, ArtificialTachycardiaVentricular Premature ComplexesHeart DiseasesCardiac Complexes, PrematureCardiac Surgical ProceduresMyocardiumEchocardiographyAtrial FibrillationVectorcardiographyTime FactorsSignal Processing, Computer-AssistedElectrophysiologic Techniques, CardiacMyocardial IschemiaBrugada SyndromeCardiomyopathiesHeart BlockCardiomegalyMyocardial ContractionTachycardia, SupraventricularHeart AtriaSyncopePredictive Value of TestsBundle-Branch BlockCardiac CatheterizationProspective StudiesDogsDefibrillators, ImplantableBody Surface Potential MappingBradycardiaTelemetryHeart FailureCatheter AblationHeart ArrestFollow-Up StudiesModels, CardiovascularAtrial FlutterDeath, SuddenBlood PressureExercise TestAutonomic Nervous SystemNAV1.5 Voltage-Gated Sodium ChannelVentricular DysfunctionTreatment OutcomeCoronary DiseaseHemodynamicsVentricular Function, LeftAction PotentialsRisk FactorsTorsades de PointesChest PainPacemaker, ArtificialStroke VolumeCardiomyopathy, DilatedElectric CountershockAmiodaroneVentricular FunctionVentricular Dysfunction, LeftPericardiumAtrioventricular BlockRetrospective StudiesMonitoring, PhysiologicCardiomyopathy, HypertrophicSensitivity and SpecificityCardiac TamponadeDiagnosis, Computer-AssistedAtrial Premature ComplexesFlecainideElectrophysiologyCreatine KinaseHypertrophy, Left VentricularHeart Defects, CongenitalPrognosisWolff-Parkinson-White SyndromeAdrenergic beta-AntagonistsPhonocardiographyAjmalineRisk AssessmentEther-A-Go-Go Potassium ChannelsHeart Function TestsMyocardial Reperfusion InjuryAtrioventricular NodeCoronary AngiographyPericarditis