Heart rate variability and pacemaker treatment in children with Fontan circulation Jenny Alenius Dahlqvist Department of Clinical Sciences, Pediatrics Department of Radiation Sciences Umeå 2019 This work is protected by the Swedish Copyright Legislation (Act 1960:729) Dissertation for PhD ISBN: 978-91-7855-007-4 ISSN: 0346-6612 New series no: 2022 Cover illustration: Sigge Mårtensgård Klüft, 6 years. Layout cover: Inhousebyrån, Umeå universitet. Electronic version available at: http://umu.diva-portal.org/ Printed by: UmU Print Service Umeå, Sweden 2019 1 To children with Fontan circulation Table of Contents Abstract ............................................................................................. 4 Background ............................................................................................................... 4 Aim ............................................................................................................................. 4 Methods ...................................................................................................................... 4 Results ........................................................................................................................ 4 Conclusions ................................................................................................................. 5 Abbreviations .................................................................................... 6 Original papers ................................................................................. 8 Sammanfattning på svenska ............................................................. 9 Bakgrund ................................................................................................................... 9 Syfte ............................................................................................................................ 9 Metoder ...................................................................................................................... 9 Resultat ...................................................................................................................... 9 Slutsats ...................................................................................................................... 10 Introduction/ Background ............................................................... 11 Univentricular heart malformations .......................................................... 11 Fontan circulation ..................................................................................... 14 Management ............................................................................................................. 14 Stage I procedures .................................................................................................... 14 Bidirectional Glenn procedure (BDG)..................................................................... 15 Completion of Fontan circulation ........................................................................... 16 Total Cavopulmonary connection (TCPC) .............................................................. 16 Physiology of the Fontan circulation .......................................................... 19 Prognosis ................................................................................................. 20 Complications .......................................................................................... 20 Arrhythmia ............................................................................................... 21 Tachyarrhythmia .................................................................................................... 22 Bradyarrhythmia .................................................................................................... 23 Pacemaker implantation ........................................................................................ 24 ECG monitoring after Fontan surgery ........................................................ 25 The autonomic control of the circulation ...................................................26 Heart rate variability (HRV) ......................................................................29 How to measure HRV ............................................................................................. 29 Spectral analysis ..................................................................................................... 30 The Poincaré diagram ............................................................................................. 31 Age- and gender dependency of HRV .................................................................... 33 Clinical application of HRV .................................................................................... 33 HRV in congenital heart disease ............................................................................ 33 HRV in univentricular heart defects and Fontan circulation .............................. 34 HRV and arrhythmia .............................................................................................. 34 Overall Aim ..................................................................................... 35 Specific Aims ............................................................................................. 35 Overview of included studies .......................................................... 36 2 Materials and Methods ................................................................... 38 Identification of the patients ..................................................................... 38 Data collection.......................................................................................... 38 Clinical data ............................................................................................................. 38 Ambulatory 24-hour electrocardiogram (Holter) ................................................ 38 Hand-held ECG ........................................................................................................ 38 ECG analysis ............................................................................................................ 39 HRV analyses ............................................................................................ 39 Power spectral analysis .......................................................................................... 40 Poincaré plots .......................................................................................................... 40 Statistical methods ................................................................................... 40 Results ............................................................................................ 43 Main findings ............................................................................................43 Patients .................................................................................................... 44 Controls .................................................................................................... 45 ECG findings (paper I, III) ........................................................................ 46 Heart Rate Variability (study I, II, III, V) .................................................. 46 Lateral tunnel (LT) versus extracardiac conduit (EC) (paper I) ......................... 46 HRV through surgical stages to TCPC (Paper II) ................................................. 48 Intermittent short-term ECG findings (paper III) ................................................ 49 HRV in patients with SND (Paper V) ...................................................................... 51 Pacemaker implantation in patients with Fontan circulation (paper IV) .... 56 Indication for pacemaker implantation ................................................................ 56 LT versus EC ............................................................................................................. 57 Pacemaker implantation in different anatomical diagnoses ............................... 58 Symptoms related to pacemaker implantation..................................................... 60 Discussion ........................................................................................ 61 Arrhythmia ............................................................................................... 61 ECG registration ...................................................................................................... 61 Bradycardia............................................................................................................. 62 Sinus node dysfunction (SND) ................................................................................ 63 Pacemaker treatment ............................................................................... 64 Heart rate variability (HRV) ..................................................................... 66 HRV and SND .......................................................................................................... 66 Other plausible reasons for low HRV in Fontan patients ..................................... 67 HRV related to surgical stages ................................................................................ 67 Conclusions ..................................................................................... 69 Acknowledgements ......................................................................... 70 References ........................................................................................