Heart BlockHeartAdams-Stokes SyndromeHeart VentriclesHeart RatePacemaker, ArtificialAtrioventricular NodeHeart Defects, CongenitalCerebral VentriclesElectrocardiographyFetal HeartRNA, Small CytoplasmicAtrioventricular BlockBradycardiaFetal DiseasesAntibodies, AntinuclearThird VentricleFourth VentricleCardiac Pacing, ArtificialHeart Conduction SystemHeart FailureMyocardiumBundle of HisHeart DiseasesHeart Rate, FetalLateral VentriclesBundle-Branch BlockHeart AtriaEchocardiographyCerebral Ventricle NeoplasmsHeart SeptumHeart Septal Defects, VentricularMaternal-Fetal ExchangeRibonucleoproteinsNerve BlockSteroids, FluorinatedCardiomyopathiesEndocardial FibroelastosisHeart TransplantationKearns-Sayre SyndromeSinoatrial NodeSyncopePregnancyInfant, NewbornMyocardial ContractionArrhythmias, CardiacTransposition of Great VesselsDogsTime FactorsHemodynamicsLupus Erythematosus, CutaneousMagnetocardiographyCardiac CatheterizationCardiomyopathy, DilatedMyocytes, CardiacAutoantigensHeart ValvesMyocardial InfarctionAutoantibodiesVentricular FunctionHydrops FetalisUltrasonography, PrenatalLupus Erythematosus, SystemicElectrocardiography, AmbulatoryPregnancy ComplicationsFollow-Up StudiesVentricular Function, LeftAutoimmune DiseasesTreatment OutcomeCardiomyopathy, HypertrophicHeart Valve ProsthesisCardiac Surgical ProceduresHeart AuscultationMyocarditisImmunity, Maternally-AcquiredEchocardiography, DopplerCollagen DiseasesPrenatal DiagnosisCatheter AblationArrhythmia, SinusBetamethasoneSick Sinus SyndromeHeart Function TestsMetoprololCardiomegalyElectrophysiologic Techniques, CardiacEndocardium