title: Right Parasternal Electrode Configuration Converts a Failed Electrocardiographic Screening to a Pass for Subcutaneous Implantable Cardioverter-Defibrillator Implantation.
abstract: BACKGROUND
  Pre-operative electrocardiographic (ECG) screening before subcutaneous implantable cardioverter-defibrillator (SICD) implantation is essential to prevent T-wave oversensing and inappropriate shocks. The failure rate of ECG screening was reported to be up to 8% when only two body positions were tested.
  
  
  METHODS
  Three subcutaneous ECG vectors represented by lead I, II and III were obtained in standing, supine, sitting and squatting positions. A patient qualified if the ECG in any same lead passed in all four positions. We report a 31-year-old man with idiopathic ventricular fibrillation who failed ECG screening for SICD implantation with the conventional left parasternal electrode (LPS) configuration in all three subcutaneous ECG vectors. Right parasternal electrode (RPS) configuration with left arm and right arm ECG electrodes positioned 1cm lateral to right sternal border was attempted for screening.
  
  
  RESULTS
  The amplitude of the QRS complex was significantly larger in the RPS compared to the LPS configuration in lead III and the patient passed the ECG screening in four body positions. He underwent successful SICD implantation with RPS approach with appropriate sensing both during the procedure and exercise treadmill test four weeks later. Ventricular fibrillation was successfully converted with 65J standard polarity shock during the procedure and no ICD shock was experienced by the patient on six-month follow-up.
  
  
  CONCLUSIONS
  RPS configuration may be considered in patients who fail the ECG screening with the conventional LPS approach for SICD implantation.
authors: Department of Medicine & Geriatrics, Princess Margaret Hospital, Hong Kong. Electronic address: ngaiyinchan@yahoo.com.hk.
authors: N Y
authors: NY
authors: Chan
authors: Department of Medicine & Geriatrics, Princess Margaret Hospital, Hong Kong.
authors: H C
authors: HC
authors: Yuen
authors: Department of Medicine & Geriatrics, Princess Margaret Hospital, Hong Kong.
authors: N S
authors: NS
authors: Mok
mesh_terms: D000328:Adult; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D006801:Humans; D008297:Male; D014693:Ventricular Fibrillation / Q000503:physiopathology* / Q000601:surgery*
keywords: Right parasternal; Screening; Subcutaneous electrocardiography; Subcutaneous implantable cardioverter-defibrillator; Sudden cardiac death