BradycardiaHeart RateApneaVagus NerveHypotensionReflexSinoatrial NodeBlood PressureArrhythmia, SinusReflex, OculocardiacAtropineHeart BlockElectrocardiographyDivingBiguanidesSick Sinus SyndromeBaroreflexSyncopePacemaker, ArtificialTachycardiaAnesthesiaVagotomyAtropine DerivativesRespirationCardiovascular SystemAtrioventricular BlockPressoreceptorsSyncope, VasovagalChemoreceptor CellsHeartMedulla OblongataArrhythmias, CardiacCardiac Pacing, ArtificialDecerebrate StateClonidineParasympatholyticsCarotid SinusParasympathetic Nervous SystemImmersionAutonomic Nervous SystemCiguatera PoisoningPostsynaptic Potential SummationSolitary NucleusAnti-Arrhythmia AgentsMicroinjectionsTorsades de PointesHeart Rate, FetalSympathetic Nervous SystemHeart ArrestSympatholyticsAortic BodiesHemodynamicsIntraoperative ComplicationsCiguatoxinsTilt-Table TestConsciousnessAtenololNeuroendoscopyCardiovascular Physiological PhenomenaAnesthesia, SpinalDogsAdrenergic beta-AntagonistsGlycopyrrolateIndoraminMuscarinic AntagonistsInfant, Premature, DiseasesPropranolol