Heart BlockHeartAdams-Stokes SyndromeHeart RatePacemaker, ArtificialAtrioventricular NodeRNA, Small CytoplasmicAtrioventricular BlockBradycardiaElectrocardiographyAntibodies, AntinuclearHeart Defects, CongenitalFetal HeartFetal DiseasesCardiac Pacing, ArtificialHeart FailureHeart Conduction SystemBundle of HisHeart Rate, FetalHeart DiseasesBundle-Branch BlockMaternal-Fetal ExchangeRibonucleoproteinsNerve BlockSteroids, FluorinatedMyocardiumKearns-Sayre SyndromeEndocardial FibroelastosisHeart TransplantationSinoatrial NodeHeart AtriaHeart SeptumEchocardiographySyncopeHeart Septal Defects, VentricularCardiomyopathiesPregnancyLupus Erythematosus, CutaneousMagnetocardiographyAutoantigensAutoantibodiesTime FactorsInfant, NewbornLupus Erythematosus, SystemicArrhythmias, CardiacHydrops FetalisPregnancy ComplicationsHeart ValvesElectrocardiography, AmbulatoryAutoimmune DiseasesCardiac CatheterizationMyocardial InfarctionMyocytes, CardiacCardiomyopathy, DilatedFollow-Up StudiesUltrasonography, PrenatalImmunity, Maternally-AcquiredHemodynamicsCollagen DiseasesArrhythmia, SinusBetamethasoneMyocarditisPrenatal DiagnosisTransposition of Great VesselsHeart AuscultationTreatment OutcomeSick Sinus SyndromeDogsHeart Valve ProsthesisMetoprolol