Defibrillators, ImplantableArrhythmias, CardiacPacemaker, ArtificialProstheses and ImplantsRadio Frequency Identification DeviceElectromagnetic RadiationHeart-Assist DevicesTelemetryDeath, Sudden, CardiacTachycardia, VentricularMonitoring, AmbulatoryElectric CountershockHeart FailureEquipment DesignElectrocardiographyTreatment OutcomeVentricular FibrillationAnti-Arrhythmia AgentsMyocytes, CardiacArrhythmia, SinusLong QT SyndromeHeart Conduction SystemHeartEquipment FailureElectrocardiography, AmbulatoryImplantable NeurostimulatorsCardiac Pacing, ArtificialTachycardiaAtrial FibrillationHeart RateVentricular Premature ComplexesEquipment SafetyHeart VentriclesSyncopeDeath, SuddenCardiac Complexes, PrematureAmiodaroneDevice RemovalNAV1.5 Voltage-Gated Sodium ChannelElectrophysiologic Techniques, CardiacMyocardiumEncainideHeart ArrestCardiac OutputTime FactorsCardiac ElectrophysiologyInfusion Pumps, ImplantableCardiac Surgical ProceduresHeart DiseasesElectrodes, ImplantedTachycardia, SupraventricularModels, CardiovascularBradycardiaFollow-Up StudiesEther-A-Go-Go Potassium ChannelsDevice ApprovalCatheter AblationCardiomyopathiesElectric InjuriesAtrial FlutterPotassium Channels, Voltage-GatedHeart AtriaMoricizineDogsAction PotentialsKCNQ1 Potassium ChannelMyocardial InfarctionEquipment Failure AnalysisProspective StudiesFlecainideMyocardial IschemiaSodium ChannelsRisk FactorsMyocardial ContractionAtrial Premature ComplexesDigitalis GlycosidesRetrospective StudiesCardiomyopathy, DilatedCardiac Resynchronization Therapy DevicesChlorofluorocarbons, MethaneBrugada SyndromeMonitoring, PhysiologicEchocardiographyProsthesis ImplantationElectrophysiologyHeart BlockKCNQ Potassium ChannelsPericardiumCardiac Resynchronization TherapyTorsades de PointesBody Surface Potential MappingRisk AssessmentStroke VolumeVentricular DysfunctionCardiac CatheterizationCardiomegalyHypokalemiaVentricular Dysfunction, LeftCardiac Imaging TechniquesHemodynamics