title: Absent right and persistent left superior vena cava: troubleshooting during a challenging pacemaker implant: a case report.
abstract: BACKGROUND
  Venous anomalies of the thorax can occur in isolation or in association with complex congenital heart disease. The incidence of an absent right superior vena cava in the setting of a persistent left superior vena cava is very rare in the general population with only a dozen cases documented in the medical literature. Such venous anomalies can make for very challenging electronic cardiac device implantation. We report our challenging dual chamber pacemaker implant in a patient with such complex anatomy and focus on our implantation technique that helped achieve adequate lead positioning.
  
  
  METHODS
  A 73-year-old Caucasian female with degenerative complete heart block presented for dual chamber permanent pacemaker implant. Lead implantation was very challenging due to abnormal and rare vena cava anatomy; a persistent left superior vena cava drained directly into the coronary sinus and the right brachiocephalic vein drained directly into the left persistent superior vena cava as the patient had an absent right superior vena cava . Adequate right ventricular lead positioning was achieved following numerous lead-stylet manipulations and careful looping in the atria to redirect its trajectory to the ventricular apex.
  
  
  CONCLUSIONS
  Abnormal superior vena cava development is uncommon and can lead to technical challenges when venous access is required during various interventional procedures. Pre-operative imaging can help identify such challenging anatomy allowing appropriate operative planning; careful patient selection is warranted for venography given the risk of contrast nephrotoxicity.
authors.forename: Jacques
authors.initials: J
authors.lastname: Rizkallah
authors.forename: John
authors.initials: J
authors.lastname: Burgess
authors.affiliation: Libin Cardiovascular Institute of Alberta, University of Calgary, C829 Foothills Medical Centre, 1403 29 Street NW, Calgary, AB T2N 2 T9, Canada. Vikas.Kuriachan@albertahealthservices.ca.
authors.forename: Vikas
authors.initials: V
authors.lastname: Kuriachan
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods; D005260:Female; D006327:Heart Block / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D010138:Pacemaker, Artificial; D054079:Vascular Malformations / Q000175:diagnosis* / Q000503:physiopathology; D014683:Vena Cava, Superior / Q000002:abnormalities*