Pulmonary VeinsCatheter AblationAtrial FibrillationPulmonary Veno-Occlusive DiseaseVeinsHeart AtriaElectrophysiologic Techniques, CardiacSaphenous VeinCryosurgeryPortal VeinVaricose VeinsHeart Conduction SystemBody Surface Potential MappingTachycardia, Ectopic AtrialBlood CirculationFemoral VeinPulmonary CirculationJugular VeinsCardiac CathetersTreatment OutcomeVena Cava, SuperiorRecurrencePhlebographyMesenteric VeinsDogsTachycardia, ParoxysmalConstriction, PathologicFluoroscopyExtracorporeal CirculationRenal VeinsUmbilical VeinsScimitar SyndromeIliac VeinAtrial SeptumAnti-Arrhythmia AgentsElectrocardiographySurgery, Computer-AssistedHepatic VeinsAutonomic DenervationAtrial Premature ComplexesFollow-Up StudiesImaging, Three-DimensionalAtrial FunctionPulmonary ArteryAtrial AppendagePopliteal VeinBreath HoldingTime FactorsAtrial Function, LeftEchocardiography, TransesophagealCatheterizationAngiographyAtrial FlutterElectrocardiography, AmbulatoryCardiac Pacing, ArtificialAzygos VeinElectrophysiological PhenomenaTomography, X-Ray ComputedCardiac Complexes, PrematureSubclavian VeinSplenic VeinCerebral VeinsCollateral CirculationBlood Flow VelocityMagnetic Resonance AngiographyEquipment DesignTachycardiaSinoatrial NodeHeart Septal Defects, AtrialCoronary SinusLymphangiectasisPulmonary AtresiaRetinal VeinTomography, Spiral ComputedRefractory Period, ElectrophysiologicalProspective StudiesPersistent Fetal Circulation SyndromeVenae CavaeBrachiocephalic VeinsVena Cava, InferiorRespiratory-Gated Imaging TechniquesEnterohepatic CirculationFeasibility StudiesGanglia, AutonomicEchocardiographyPericardiumVascular MalformationsCoronary CirculationCardiac Surgical ProceduresCerebrovascular CirculationMultidetector Computed TomographyPostoperative ComplicationsAxillary VeinRetinal Vein OcclusionLiver Circulation