Pulmonary VeinsCatheter AblationAtrial FibrillationPulmonary Veno-Occlusive DiseaseVeinsHeart AtriaElectrophysiologic Techniques, CardiacSaphenous VeinCryosurgeryPortal VeinVaricose VeinsHeart Conduction SystemBody Surface Potential MappingTachycardia, Ectopic AtrialFemoral VeinCardiac CathetersJugular VeinsTreatment OutcomeVena Cava, SuperiorRecurrencePhlebographyTachycardia, ParoxysmalFluoroscopyMesenteric VeinsScimitar SyndromeRenal VeinsConstriction, PathologicUmbilical VeinsIliac VeinAtrial SeptumAnti-Arrhythmia AgentsSurgery, Computer-AssistedElectrocardiographyAutonomic DenervationAtrial Premature ComplexesDogsHepatic VeinsAtrial AppendageImaging, Three-DimensionalPopliteal VeinAtrial FunctionFollow-Up StudiesBreath HoldingAtrial Function, LeftEchocardiography, TransesophagealAtrial FlutterElectrocardiography, AmbulatoryCardiac Pacing, ArtificialAzygos VeinElectrophysiological PhenomenaCardiac Complexes, PrematureCatheterizationSubclavian VeinPulmonary ArteryAngiographySplenic VeinTomography, X-Ray ComputedCerebral VeinsSinoatrial NodePulmonary CirculationTime FactorsLymphangiectasisTachycardiaHeart Septal Defects, AtrialCoronary SinusEquipment DesignTomography, Spiral ComputedRefractory Period, ElectrophysiologicalMagnetic Resonance AngiographyRetinal VeinPulmonary AtresiaBrachiocephalic VeinsRespiratory-Gated Imaging TechniquesGanglia, AutonomicProspective StudiesVenae CavaeMultidetector Computed TomographyFeasibility StudiesPericardiumAxillary VeinVascular MalformationsEchocardiography