SympathectomyDefibrillators, Implantable3-IodobenzylguanidineGanglionectomyAutonomic Nervous System DiseasesTachycardia, VentricularSympathetic Nervous SystemIodobenzenesDenervationHeartEquipment FailureElectric CountershockDeath, Sudden, CardiacElectric InjuriesVentricular FibrillationArrhythmias, CardiacIodine RadioisotopesMuscle DenervationAutonomic DenervationPacemaker, ArtificialDevice RemovalEquipment SafetyEquipment Failure AnalysisSympathectomy, ChemicalStellate GanglionElectrodes, ImplantedEphedrineAmiodaroneElectrocardiographyAnti-Arrhythmia AgentsCardiac Pacing, ArtificialTreatment OutcomeShy-Drager SyndromeSyncopeHeart FailureBrugada SyndromeProsthesis ImplantationHeart ArrestEquipment DesignCardiac Resynchronization TherapyMagnetsSympatholyticsAtrial RemodelingFollow-Up StudiesElectromagnetic PhenomenaCatheter AblationAdrenergic FibersNorepinephrineCardiac Resynchronization Therapy DevicesRemote Sensing TechnologyTime FactorsElectrophysiologic Techniques, CardiacCardiomyopathiesElectrocardiography, AmbulatoryHyperhidrosisHeart RateCatecholaminesRenal ArteryRisk AssessmentTelemetryBlood PressureEmergency Medical TagsImplantable NeurostimulatorsVentricular Dysfunction, LeftStroke VolumeArrhythmogenic Right Ventricular DysplasiaPrimary PreventionCardiomyopathy, DilatedVentricular DysfunctionMyocytes, CardiacTachycardia, SupraventricularBiomedical EnhancementPacific StatesTyramineTachycardiaProspective StudiesHealth ResortsRisk FactorsTachycardia, SinusRetrospective StudiesTherapy, Computer-AssistedKidneyOxidopamineLong QT SyndromeHypertensionHeart DiseasesRadiopharmaceuticalsDeath, SuddenTelemedicineProstheses and ImplantsSecondary PreventionSurvival RateCardiac OutputParasympathetic Nervous SystemDogsHeart VentriclesInfusion Pumps, ImplantableProsthesis-Related InfectionsMyocardial IschemiaAtrial Fibrillation