title: Inadequacy of fluoroscopy and electrocardiogram in predicting septal position in RVOT pacing - Validation with cardiac computed tomography.
abstract: BACKGROUND
  Electrocardiographic (ECG) and fluoroscopic criteria, which are the only available guides to achieve a true septal position during right ventricular outflow tract (RVOT) pacing, have been infrequently validated. We sought to validate these using cardiac computed tomographic angiography (CTA) to confirm lead position within the RVOT septum.
  
  
  METHODS
  Forty-four patients with permanent pacemaker leads in the RVOT position underwent CTA. Lead positions in RVOT were classified as anterior, free wall, or septal location. Fluoroscopic images were obtained in 4 standard views.
  
  
  RESULTS
  Only 19 (43%) patients had lead in true septal position within the RVOT in CTA while 25 patients (57%) were found to have an anterior lead location. Mean QRS axis, QRS duration, negative QRS in lead I, and notching in inferior leads were not significantly different between the two groups. The standard fluoroscopic LAO view showed a rightward-directed lead not only in all 19 patients with septal location, but also in 14/25 patients in the anterior location (p=0.22), and thus had a sensitivity of 100% but specificity of only 16% in predicting true septal position. The posteriorly directed lead in left lateral view was more accurate in predicting true septal position with good sensitivity (73.7%) and excellent specificity (80%).
  
  
  CONCLUSIONS
  This study, using validation with CTA, showed that conventional ECG criteria and fluoroscopy are inaccurate in differentiating septal from anterior RVOT pacing. The fluoroscopic lateral view, as corroborated by CTA, is more reliable than the LAO view in predicting septal lead placement.
authors.affiliation: Professor and Head, Department of Cardiology, All India Institute of Medical Sciences, New Delhi 110029, India. Electronic address: drsharmagautam@gmail.com.
authors.forename: Gautam
authors.initials: G
authors.lastname: Sharma
authors.affiliation: Senior Resident, Department of Cardiology, All India Institute of Medical Sciences, New Delhi 110029, India.
authors.forename: Salman
authors.initials: S
authors.lastname: Salahuddin
authors.affiliation: Director, Centre for Heart Rhythm Disorders, University of Adelaide, Royal Adelaide Hospital, Adelaide 5000, Australia.
authors.forename: Prashanthan
authors.initials: P
authors.lastname: Sanders
authors.affiliation: Senior Resident, Department of Cardiology, All India Institute of Medical Sciences, New Delhi 110029, India.
authors.forename: Himanshu
authors.initials: H
authors.lastname: Gupta
authors.affiliation: Professor, Department of Cardio Vascular and Interventional Radiology, All India Institute of Medical Sciences, New Delhi 110029, India.
authors.forename: Gurpreet
authors.initials: G
authors.lastname: Gulati
authors.affiliation: Additional Professor, Department of Cardio Vascular and Interventional Radiology, All India Institute of Medical Sciences, New Delhi 110029, India.
authors.forename: Priya
authors.initials: P
authors.lastname: Jagia
authors.affiliation: Professor and Head, Department of Cardiology, All India Institute of Medical Sciences, New Delhi 110029, India.
authors.forename: V K
authors.initials: VK
authors.lastname: Bahl
mesh_terms: D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D000072226:Computed Tomography Angiography / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D005471:Fluoroscopy / Q000379:methods*; D006346:Heart Septum / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods; D010138:Pacemaker, Artificial; D015203:Reproducibility of Results
keywords: Cardiac computed tomography; Fluoroscopy; Right ventricular outflow tract (RVOT) septal pacing