ElectrocardiographyPacemaker, ArtificialElectrocardiography, AmbulatoryHeart BlockArrhythmias, CardiacBiological ClocksSinoatrial NodeEchocardiographyExercise TestSick Sinus SyndromeBradycardiaAtrioventricular BlockMagnetocardiographyHeart Conduction SystemVectorcardiographyEquipment FailureHeart RateSignal Processing, Computer-AssistedHeartChest PainSyncopeMyocardial InfarctionAtrial FibrillationProspective StudiesHyperpolarization-Activated Cyclic Nucleotide-Gated ChannelsHypertrophy, Left VentricularPredictive Value of TestsHeart DiseasesTelemetrySensitivity and SpecificityHeart AuscultationAtrioventricular NodeCoronary AngiographyDeath, Sudden, CardiacCoronary DiseaseTachycardiaCardiomyopathiesTime FactorsMyocardial IschemiaDipyridamoleThalliumTachycardia, SinusHeart AtriaFollow-Up StudiesBundle-Branch BlockCircadian RhythmCardiotocographyPeripartum PeriodCardiologyKinetocardiographyDobutamineHeart VentriclesMonitoring, PhysiologicElectrodes, ImplantedInterstitial Cells of CajalDefibrillators, ImplantableTachycardia, SupraventricularTachycardia, VentricularSuprachiasmatic NucleusVentricular Premature ComplexesAction PotentialsTreatment OutcomeDevice RemovalCardiomyopathy, HypertrophicAngina PectorisPrognosisWolff-Parkinson-White SyndromeElectrodesVentricular Dysfunction, LeftRadionuclide VentriculographyEquipment SafetyCardiology Service, HospitalRisk FactorsAnti-Arrhythmia AgentsCyclic Nucleotide-Gated Cation ChannelsPeriodicityEmergency Medical TechniciansHeart Function TestsTroponin TAutonomic Nervous SystemVentricular Function, LeftRadiography, ThoracicRetrospective StudiesPericarditisThallium RadioisotopesHeart FailureCardiovascular AbnormalitiesPhonocardiographyStroke VolumeEchocardiography, DopplerCoronary Artery DiseaseElectrophysiologyPhysical ExaminationDogsCardiac CatheterizationTakotsubo CardiomyopathyCardiotonic AgentsFlufenamic AcidDeath, SuddenHeart Murmurs