title: Pacemaker-induced superior vena cava syndrome: clinical evaluation of long-term follow-up.
abstract: BACKGROUND
  Pacemaker-induced superior vena cava (SVC) syndrome is a rare but serious complication of permanent pacemaker implantation. Because of its rarity, little is known about the long-term prognoses of such patients.
  
  
  METHODS
  Five patients, mean age 62 +/- 11.4 years, with pacemaker-induced SVC syndrome for more than 10 years were investigated. The clinical evaluation included: exercise testing, thrombophilia lab tests, and a chest CT.
  
  
  RESULTS
  Two of the patients manifested complications of SVC syndrome which included thoracoabdominal subcutaneous collaterals. One of these patients simultaneously developed an increase in the pacing threshold which required the implantation of epicardial leads. Three of the five patients had normal age-adjusted VO(2) AT und VO(2) max. Four of the patients were both heterozygous for a polymorphism of PAI-1 and were homozygous for a polymorphism of t-PA. One of these patients also was heterozygous for a polymorphism of factor V and glycoprotein IIb/IIIa. The chest CTs revealed extensive and varying collateral circulation patterns in all of the patients.
  
  
  CONCLUSIONS
  The development of pacemaker-induced SVC syndrome is the result of various predisposing factors including thrombophilia. Many patients retain normal age-adjusted cardiopulmonary capacity and demonstrate stable clinical findings on the long-term as the result of the development of extensive collateral vessel systems. The most serious complication was the combination of SVC syndrome and the simultaneous malfunctioning of one of the leads requiring implantation of a new lead.
authors.affiliation: Department of Internal Medicine, Clinic for Cardiology and Angiology, Charité University Medical Center, Berlin, Germany. christoph.melzer@charite.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Melzer
authors.forename: Alexander
authors.initials: A
authors.lastname: Lembcke
authors.forename: Sabine
authors.initials: S
authors.lastname: Ziemer
authors.forename: Stephan
authors.initials: S
authors.lastname: Eddicks
authors.forename: Joachim
authors.initials: J
authors.lastname: Witte
authors.forename: Gert
authors.initials: G
authors.lastname: Baumann
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Borges
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects*; D004868:Equipment Failure; D019544:Equipment Failure Analysis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial / Q000009:adverse effects*; D013479:Superior Vena Cava Syndrome / Q000175:diagnosis / Q000209:etiology* / Q000517:prevention & control*; D016896:Treatment Outcome