title: Left superior vena cava persistence in patients undergoing pacemaker or cardioverter-defibrillator implantation: a 10-year experience.
abstract: OBJECTIVE
  The persistence of a left superior vena cava (LSVC) has been observed in 0.3% of the general population as established by autopsy. In the adult population, it is an important anatomic finding if a left superior approach to the heart is considered. The aim of the study was to evaluate the prevalence of a LSVC in patients undergoing pacemaker (PM) and cardioverter-defibrillator (CD) implantation.
  
  
  METHODS
  We observed the prevalence of LSVC during a 10-year period; each patient undergoing PM or transvenous CD implantation received a left cephalic/left subclavian venous approach to the heart. With this technique, LSVC persistence is easily diagnosed during lead placement.
  
  
  RESULTS
  A total of 1,139 patients consecutively underwent PM implantation during 10 years: 4 patients had persistent LSCV (0.34%). Among 115 patients undergoing CD implantation, 2 patients with LSVC (1.7%) were observed. Overall LSVC persistence was found in 6 of 1,254 patients (0.47%). Two patients, one of whom had no right superior vena cava (RSVC), received a left-sided PM, whereas two other patients received right-sided devices. Both CD patients received a left-sided active-can device: the first patient with a right-sided lead tunneled to the left pectoral pocket, as a result of poor catheter handling through the LSVC and coronary sinus, and the second patient with a screw-in lead from LSVC. Long-term follow-up of these patients (average +/- SD, 41 +/- 26 months) revealed absence of lead dislodgment and appropriate device function regardless of lead implantation site.
  
  
  CONCLUSIONS
  Persistence of LSVC in adults undergoing PM/CD implantation is similar to that of the general population (0.47% in our study). The left-sided implant can be achieved by stylet shaping and by use of active fixation leads in most patients, with a reliable outcome at short term in addition to appropriate device performance at follow-up. Assessment of the RSVC is advisable when planning a right-sided implantation, since a minority of patients lacks this vessel.
authors.affiliation: Institute of Cardiology, University of Bologna, Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Biffi
authors.forename: G
authors.initials: G
authors.lastname: Boriani
authors.forename: L
authors.initials: L
authors.lastname: Frabetti
authors.forename: G
authors.initials: G
authors.lastname: Bronzetti
authors.forename: A
authors.initials: A
authors.lastname: Branzi
mesh_terms: D017147:Defibrillators, Implantable; D005260:Female; D006327:Heart Block / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011446:Prospective Studies; D012804:Sick Sinus Syndrome / Q000628:therapy; D017180:Tachycardia, Ventricular / Q000628:therapy; D014683:Vena Cava, Superior / Q000002:abnormalities*