Atrial AppendageCatheter AblationHeart AtriaEchocardiography, TransesophagealAtrial Function, LeftAtrial FibrillationThromboembolismAblation TechniquesElectric CountershockThrombosisHeart AneurysmPulmonary VeinsElectrophysiologic Techniques, CardiacAtrial FunctionSeptal Occluder DeviceHeart DiseasesAtrial SeptumTachycardia, Ectopic AtrialCardiac Pacing, ArtificialAtrial FlutterMitral Valve StenosisProstheses and ImplantsCardiac Surgical ProceduresAnticoagulantsPericardiumAtrial Function, RightTreatment OutcomeRheumatic Heart DiseaseFeasibility StudiesHeart Conduction SystemBlood Flow VelocityCardiac CatheterizationCardiac CathetersEmbolismSick Sinus SyndromeEchocardiographyElectrocardiographyDogsWarfarinTherapeutic OcclusionEchocardiography, Doppler, PulsedVena Cava, SuperiorHeart SeptumEchocardiography, Three-DimensionalRefractory Period, ElectrophysiologicalPericardial EffusionHeart BlockHeart Valve DiseasesExtremitiesMitral ValveStrokeSinoatrial NodeEndocardiumCarcinoma, Skin AppendageFollow-Up StudiesPacemaker, ArtificialEchocardiography, DopplerCoronary ThrombosisFluoroscopyBalloon OcclusionTime FactorsMyocardiumCefamandoleIntracranial EmbolismHeart Septal DefectsPremedicationMyocardial StunningProspective StudiesHeart Defects, CongenitalBalloon ValvuloplastyHigh-Intensity Focused Ultrasound AblationAnti-Arrhythmia AgentsPredictive Value of Tests