title: Clinical and technical determinants of long-term performance of coronary sinus leads.
abstract: OBJECTIVE
  Little is known about coronary sinus lead performance in patients with cardiac resynchronization therapy devices. We evaluated the impact of clinical and technical parameters on coronary sinus lead performance over long-term follow-up.
  
  
  METHODS
  From February 1999 to July 2004, 235 patients (181 men; mean age, 68 +/- 9 years; mean left ventricular ejection fraction, 26.5 +/- 6.5%; idiopathic dilated cardiomyopathy, 49%; ischemic, 48%; and other cause, 3%) underwent cardiac resynchronization therapy (pacemaker or defibrillator) implantation.
  
  
  RESULTS
  On implantation, the only statistically significant difference was observed in mean pacing impedance, which was lower for unipolar leads than for bipolar leads (763 +/- 250 vs. 847 +/- 270 Omega, P = 0.02), and lower in patients with ischemic cardiomyopathy than in those with idiopathic cardiomyopathy (758 +/- 204 vs. 837 +/- 291 Omega, P = 0.03). After a mean follow-up of 41.7 +/- 14.7 months, a significant decrease was observed in mean pacing impedance (from 811 +/- 261 to 717 +/- 284 Omega, P = 0.0026) and mean R-wave amplitude (from 13.2 +/- 6.7 to 10.5 +/- 5.5 mV, P = 0.002), whereas the mean pacing energy threshold increased from 3.6 +/- 10.4 to 9.5 +/- 28 microJ (P = 0.004). On analysis of variance, unipolar lead (P = 0.016) and posterior coronary sinus position (P = 0.049) were related to a greater energy threshold increase. On multivariate analysis (Cox regression), only posterior coronary sinus lead position (P = 0.013) proved to be an independent predictor of long-term significant increase in the stimulation energy threshold.
  
  
  CONCLUSIONS
  Over the long-term follow-up of coronary sinus leads, pacing impedance and R-wave amplitude decreased, whereas the energy threshold increased; unipolar leads and posterior lead location in the coronary sinus were related to a greater energy threshold increase.
authors.affiliation: Casa di Cura San Michele, Maddaloni (CE), Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: La Rocca
authors.forename: Emanuele
authors.initials: E
authors.lastname: Bertaglia
authors.forename: Francesco
authors.initials: F
authors.lastname: Solimene
authors.forename: Michele
authors.initials: M
authors.lastname: Accogli
authors.forename: Assunta
authors.initials: A
authors.lastname: Iuliano
authors.forename: Natale
authors.initials: N
authors.lastname: Marrazzo
authors.forename: Gabriele
authors.initials: G
authors.lastname: De Luca De Masi
authors.forename: Alberto
authors.initials: A
authors.lastname: Scaccia
authors.forename: Giovanni
authors.initials: G
authors.lastname: Donnici
authors.forename: Paola
authors.initials: P
authors.lastname: Chiariello
authors.forename: Pietro
authors.initials: P
authors.lastname: Turco
authors.forename: Antonio
authors.initials: A
authors.lastname: De Simone
authors.forename: Carmine
authors.initials: C
authors.lastname: Ciardiello
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Stabile
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects; D054326:Coronary Sinus / Q000503:physiopathology*; D017147:Defibrillators, Implantable / Q000009:adverse effects; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation*; D017097:Electric Impedance; D004867:Equipment Design; D004868:Equipment Failure; D019544:Equipment Failure Analysis; D005260:Female; D006331:Heart Diseases / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010138:Pacemaker, Artificial / Q000009:adverse effects; D016016:Proportional Hazards Models; D018570:Risk Assessment; D013997:Time Factors; D016896:Treatment Outcome