Defibrillators, ImplantableAccelerated Idioventricular RhythmDeath, Sudden, CardiacEquipment FailurePacemaker, ArtificialDefibrillatorsArrhythmias, CardiacElectrocardiographyElectric CountershockTachycardia, VentricularVentricular FibrillationHeart ArrestElectric InjuriesEquipment SafetyCardiac Pacing, ArtificialElectrodes, ImplantedCardiac Resynchronization TherapyDevice RemovalAnti-Arrhythmia AgentsImplantable NeurostimulatorsEquipment DesignMyocytes, CardiacAmiodaroneHeart FailureProstheses and ImplantsEquipment Failure AnalysisSyncopeCardiopulmonary ResuscitationTreatment OutcomeCardiac Resynchronization Therapy DevicesProsthesis ImplantationFollow-Up StudiesInfusion Pumps, ImplantableOut-of-Hospital Cardiac ArrestCardiac OutputCardiomyopathiesVentricular Dysfunction, LeftHeartStroke VolumeElectrophysiologic Techniques, CardiacTachycardiaTelemetryElectrocardiography, AmbulatoryTime FactorsProspective StudiesHeart DiseasesCardiac Electrophysiology