Atrial AppendageSeptal Occluder DeviceAtrial FibrillationEchocardiography, TransesophagealHeart AtriaAtrial Function, LeftThromboembolismThrombosisElectric CountershockHeart AneurysmAtrial FunctionHeart DiseasesBalloon OcclusionCatheter AblationExtremitiesAtrial SeptumAtrial FlutterProstheses and ImplantsCarcinoma, Skin AppendageMitral Valve StenosisBlood Flow VelocityTherapeutic OcclusionCardiac Pacing, ArtificialAnticoagulantsPulmonary VeinsCardiac Surgical ProceduresDogsEmbolismAtrial Function, RightRheumatic Heart DiseaseElectrophysiologic Techniques, CardiacCardiac CatheterizationTachycardia, Ectopic AtrialFeasibility StudiesCoronary OcclusionPericardiumSick Sinus SyndromeTreatment OutcomeEchocardiography