title: Long-term performance of coronary sinus leads used for cardiac resynchronization therapy.
abstract: BACKGROUND
  Little is known regarding the long-term performance of coronary sinus (CS) leads, which have an effect on the longevity of cardiac resynchronization therapy (CRT) systems.
  
  
  METHODS
  This study included 109 patients (79 men) whose mean age was 68 +/- 9 years, New York Heart Association (NYHA) functional class 3.2 +/- 0.5, and left ventricular ejection fraction 25.6 +/- 6.6%, and who underwent CRT (n = 45) or CRT-D (n = 64) systems implants for management of idiopathic (53%), ischemic (40%), or miscellaneous (7%) dilated cardiomyopathy. Unipolar (n = 57) or bipolar (n = 52) leads were placed into the CS venous system.
  
  
  RESULTS
  At implant, no significant difference was observed between unipolar and bipolar leads with respect to mean sensing performance (14 +/- 6 mV vs 14 +/- 8 mV, P = 0.97), pacing impedance (875 +/- 234 ohms vs 943 +/- 331 ohms, P = 0.24), and stimulation energy threshold (2 +/- 3.2 muJ vs 1.13 +/- 1.5 muJ, P = 0.08). At a median follow-up of 33 months, a significant decrease in stimulation impedance and increase in stimulation energy threshold was observed with unipolar (689 +/- 122 vs 875 +/- 234 ohms, P < 0.01, and 8.34 +/- 10.4 muJ vs 2 +/- 3.2 muJ, P < 0.001, respectively) as well as with bipolar (735 +/- 268 ohms vs 943 +/- 331 ohms, P < 0.01, and 4.81 +/- 9.92 vs 1.13 +/- 1.5 muJ, P = 0.02, respectively) leads. No significant difference in sensing performance was observed with either type of lead (10 +/- 5 mV vs 14 +/- 6 mV and 10 +/- 6 mV vs 14 +/- 8 mV, respectively). At long-term follow-up, no significant difference among any sensing or stimulation parameter was observed between unipolar and bipolar leads.
  
  
  CONCLUSIONS
  At long-term follow-up, a significant increase in the energy required for stimulation was observed, whereas sensing performance remained unchanged. The increase in energy capture threshold was less marked with bipolar than with unipolar leads.
authors.affiliation: Casa di Cura San Michele, Maddaloni (CE), Italy.
authors.forename: Assunta
authors.initials: A
authors.lastname: Iuliano
authors.forename: Gergana
authors.initials: G
authors.lastname: Shopova
authors.forename: Antonio
authors.initials: A
authors.lastname: De Simone
authors.forename: Francesco
authors.initials: F
authors.lastname: Solimene
authors.forename: Pietro
authors.initials: P
authors.lastname: Turco
authors.forename: Natale
authors.initials: N
authors.lastname: Marrazzo
authors.forename: Vincenzo
authors.initials: V
authors.lastname: La Rocca
authors.forename: Carmine
authors.initials: C
authors.lastname: Ciardiello
authors.forename: Marco
authors.initials: M
authors.lastname: Agrusta
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Stabile
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D054326:Coronary Sinus; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial / Q000592:standards*; D016896:Treatment Outcome