title: Alternate site right ventricular pacing: defining template scoring.
abstract: BACKGROUND
  Prolonged right ventricular (RV) apical pacing produces dysynchronous ventricular contraction, which may result in left ventricular (LV) dysfunction, whereas septal pacing sites might reflect a more synchronous LV activation. This study examined a method of evaluating alternate RV pacing sites using a template scoring system based on measuring the angle of lead attachment in the 40° left anterior oblique (LAO) fluoroscopic view and its effect on altering the loop of lead in the RV.
  
  
  METHODS
  Twenty-three consecutive patients for RV pacing were enrolled. Conventional active fixation leads were positioned in either the RV outflow tract (RVOT) or mid RV using a stylet designed for septal placement (Model 4140, St. Jude Medical, St. Paul, MN, USA). Using LAO cine fluoroscopy, a generous loop of lead was inserted into the RV chamber and the change in angle of attachment determined.
  
  
  RESULTS
  Successful positioning of pacing leads at the RVOT septum (18 patients) and mid-RV septum (five patients) was achieved. With introduction of more lead into the RV chamber, the angle of attachment in the LAO projection altered over a range of 6°-32° for all patients with a mean of 14.6 ± 6.6°. In 87% of patients, the range was predominantly within the same template score with only minor overlap into another zone.
  
  
  CONCLUSIONS
  This study shows that the angle of lead attachment in the RV is altered by introducing more lead, but in most cases, the template score remains the same. Further studies are required to determine the accuracy and efficacy of the templates.
authors: Department of Cardiology, Royal Melbourne Hospital, Melbourne, Australia. hmond@bigpond.net.au
authors: Harry G
authors: HG
authors: Mond
authors: Alexander
authors: A
authors: Feldman
authors: Saurabh
authors: S
authors: Kumar
authors: Raphael
authors: R
authors: Rosso
authors: Thuy To
authors: TT
authors: Hung
authors: Ben
authors: B
authors: Pang