Atrial AppendageEchocardiography, TransesophagealHeart AtriaAtrial Function, LeftAtrial FibrillationThromboembolismElectric CountershockSeptal Occluder DeviceThrombosisHeart AneurysmAtrial FunctionHeart DiseasesProstheses and ImplantsCatheter AblationAtrial SeptumAtrial FlutterMitral Valve StenosisCardiac Pacing, ArtificialAnticoagulantsCardiac Surgical ProceduresPulmonary VeinsAtrial Function, RightEmbolismRheumatic Heart DiseaseBlood Flow VelocityCardiac CatheterizationElectrophysiologic Techniques, CardiacTachycardia, Ectopic AtrialFeasibility StudiesDevice ApprovalSick Sinus SyndromePericardiumEchocardiographyTherapeutic OcclusionWarfarinEchocardiography, Doppler, PulsedTreatment OutcomeDogsCardiac CathetersEchocardiography, Three-DimensionalStrokeExtremitiesVena Cava, SuperiorHeart Valve DiseasesRefractory Period, ElectrophysiologicalPericardial EffusionPacemaker, ArtificialBalloon OcclusionCarcinoma, Skin AppendageHeart Conduction SystemMitral ValveCoronary ThrombosisEchocardiography, DopplerElectrocardiographyEquipment DesignSinoatrial NodeIntracranial EmbolismCefamandoleHeart BlockHeart Septal DefectsHeart SeptumMyocardiumPremedicationEndocardiumMyocardial StunningBalloon ValvuloplastyIntrauterine DevicesTime FactorsSuture TechniquesSuturesProspective StudiesFollow-Up StudiesHeart Defects, CongenitalEquipment SafetyProsthesis DesignObserver VariationCardiopulmonary Bypass