Electrocardiography, AmbulatoryArrhythmias, CardiacElectrocardiographyVentricular Premature ComplexesAtrial Premature ComplexesHeart RateAtrial FibrillationAutonomic Nervous SystemCardiac Complexes, PrematureTachycardia, VentricularMonitoring, PhysiologicDeath, Sudden, CardiacSyncopeSick Sinus SyndromeAnti-Arrhythmia AgentsSignal Processing, Computer-AssistedArrhythmia, SinusCatheter AblationTelemetryFollow-Up Studies