title: Left and Right Parasternal Sensing for the S-ICD in Adult Congenital Heart Disease Patients and Normal Controls.
abstract: BACKGROUND
  This study investigated the impact of a right parasternal sensing electrode position on the R- and T-wave amplitudes and the R:T ratio in three subcutaneous implantable cardioverter defibrillator (S-ICD) vectors in patients with adult congenital heart disease (ACHD) and normal controls.
  
  
  METHODS
  Conventional left parasternal sensing electrode position and right parasternal sensing electrode positions were used to collect 10-second electrograms, recorded through an 80-electrode body surface mapping technology (Prime ECG™ system, Heartscape Technologies Inc., now Verathon, Columbia, MD, USA). Recordings were made in the supine, prone, left lateral, right lateral, sitting, and standing positions in using both the standard electrode vector position and the right parasternal positions.
  
  
  RESULTS
  Forty patients were recruited and 37 patients were used for analysis. Twenty-seven (73%) had complex ACHD; 10 patients had normal hearts and acted as controls. A total of 3,708 data points were analyzed. There were no significant differences in the R:T ratio when measured in ACHD patients in the right compared to the left parasternal lead position. In contrast, there were important differences in the magnitude of the R:T ratio when measured in control patients in the right compared to the left parasternal lead position; in the primary vector, the R:T ratio was greater in right than left by 2.99 (P = 0.0002; 95% confidence interval [CI]: 1.48-4.50) and in the secondary vector, the R:T ratio was smaller in the right than in the left by 0.77 (P = 0.004; 95% CI: -1.58-0.05).
  
  
  CONCLUSIONS
  In selected patients, a right parasternal lead position may provide a useful alternative sensing configuration for the S-ICD.
authors.affiliation: Cardiovascular Research Department, University Hospital Southampton and Faculty of Medicine, University of Southampton, United Kingdom.
authors.forename: David G
authors.initials: DG
authors.lastname: Wilson
authors.affiliation: Cardiovascular Research Department, University Hospital Southampton and Faculty of Medicine, University of Southampton, United Kingdom.
authors.forename: Mehmood
authors.initials: M
authors.lastname: Zeb
authors.affiliation: Cardiovascular Research Department, University Hospital Southampton and Faculty of Medicine, University of Southampton, United Kingdom.
authors.forename: Gruschen
authors.initials: G
authors.lastname: Veldtman
authors.affiliation: Academic Unit of Primary Care and Population Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.
authors.forename: Borislav D
authors.initials: BD
authors.lastname: Dimitrov
authors.affiliation: Cardiovascular Research Department, University Hospital Southampton and Faculty of Medicine, University of Southampton, United Kingdom.
authors.forename: John M
authors.initials: JM
authors.lastname: Morgan
mesh_terms: D000328:Adult; D017147:Defibrillators, Implantable; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000628:therapy*; D006333:Heart Failure / Q000175:diagnosis* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D012016:Reference Values; D013249:Sternum; D016896:Treatment Outcome
keywords: adult congenital heart disease; right parasternal lead; sensing; subcutaneous implantable cardioverter defibrillators