title: Detection of perfusion abnormalities in patients with permanent pacemakers on stress-rest 99mTc-tetrofosmin myocardial perfusion single-photon emission computed tomography: comparison between right ventricular apex and right ventricular outflow tract pacing.
abstract: OBJECTIVE
  The aim of the study was to compare the myocardial perfusion defects in patients with right ventricular outflow tract (RVOT) and right ventricular apex (RVA) pacing on stress-rest Tc-tetrofosmin myocardial perfusion single-photon emission computed tomography.
  
  
  METHODS
  A total of 31 patients with permanent pacemakers (RVOT: 16 and RVA: 15) underwent stress-rest Tc-tetrofosmin involving a 1-day protocol. All patients underwent 1-day low-dose stress-gated and high-dose rest-gated Tc-tetrofosmin myocardial perfusion single-photon emission computed tomography imaging.
  
  
  RESULTS
  Fixed perfusion defects were noted in 13 (42%) of 31 patients. Two (13%) patients of the RVOT group and 11 (69%) patients of the RVA group showed fixed perfusion defects (P=0.003). The fixed perfusion defects were located in the anteroapical, anteroseptal, and apical in the RVOT pacing group and in the apical, distal anteroseptal, inferoapical, distal anterior, and distal inferoseptal in the RVA pacing group. On univariate analysis, the incidence of perfusion defects was significantly associated with apical pacing, longer pQRS duration, and higher percentage of ventricular pacing. On multivariate analysis, the site of pacemaker insertion was found to be the most important pacemaker parameter determining the incidence of perfusion defects. Importantly, the duration of postpacemaker implantation did not show any significant relation to the incidence of perfusion defects.
  
  
  CONCLUSIONS
  Fixed perfusion abnormalities are observed in patients with pacemakers and are independent of duration of time since implantation. RVOT pacing is associated with fewer incidences of myocardial perfusion abnormalities compared with RVA pacing.
authors.affiliation: aDepartment of Nuclear Medicine bDepartment of Cardiology, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India.
authors.forename: Kalpa J
authors.initials: KJ
authors.lastname: Das
authors.forename: Chetan D
authors.initials: CD
authors.lastname: Patel
authors.forename: Gautam
authors.initials: G
authors.lastname: Sharma
authors.forename: Nitish
authors.initials: N
authors.lastname: Naik
authors.forename: Harmandeep
authors.initials: H
authors.lastname: Singh
mesh_terms: D000328:Adult; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D010138:Pacemaker, Artificial; D012146:Rest; D013312:Stress, Physiological; D015899:Tomography, Emission-Computed, Single-Photon; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology; D055815:Young Adult
chemical_list: D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; C078700:technetium tc-99m tetrofosmin