Atrial AppendageEchocardiography, TransesophagealHeart AtriaAtrial Function, LeftAtrial FibrillationThromboembolismElectric CountershockThrombosisHeart AneurysmSeptal Occluder DeviceAtrial FunctionHeart DiseasesCatheter AblationAtrial SeptumAtrial FlutterMitral Valve StenosisProstheses and ImplantsCardiac Pacing, ArtificialAnticoagulantsPulmonary VeinsCardiac Surgical ProceduresAtrial Function, RightRheumatic Heart DiseaseBlood Flow VelocityTachycardia, Ectopic AtrialElectrophysiologic Techniques, CardiacEmbolismSick Sinus SyndromePericardiumCardiac CatheterizationFeasibility StudiesEchocardiographyTherapeutic OcclusionEchocardiography, Doppler, PulsedWarfarinDogsCardiac CathetersEchocardiography, Three-DimensionalExtremitiesVena Cava, SuperiorRefractory Period, ElectrophysiologicalStrokePericardial EffusionHeart Valve DiseasesCarcinoma, Skin AppendageTreatment OutcomeHeart Conduction SystemMitral ValveCoronary ThrombosisEchocardiography, DopplerSinoatrial NodeCefamandoleElectrocardiographyBalloon OcclusionHeart BlockIntracranial EmbolismPacemaker, ArtificialHeart SeptumHeart Septal DefectsMyocardiumMyocardial StunningPremedicationEndocardiumBalloon ValvuloplastyHeart Defects, Congenital