title: Long-term effects of upgrading from right ventricular pacing to cardiac resynchronization therapy in patients with heart failure.
abstract: OBJECTIVE
  To determine the effects of upgrading from right ventricular (RV) pacing to cardiac resynchronization therapy (CRT) in patients with heart failure.
  
  
  RESULTS
  Patients with heart failure [age 67.3 +/- 9.6 years (mean +/- SD), NYHA class III or IV, left ventricular ejection fraction (LVEF) <or= 35%, QRS >or= 120 ms] underwent de novo CRT (n = 336) or upgrading from RV pacing [n = 58; VVIR in 24, DDDR in 34] to CRT. The endpoint of death from any cause or major cardiovascular events, cardiovascular death or hospitalization for heart failure, and cardiovascular death or death from any cause was determined after a maximum follow-up of 7.7 years. No differences emerged between the de novo CRT and the upgrade-to-CRT groups with respect to any of the clinical endpoints. The de novo CRT and upgrade-to-CRT groups derived similar improvements in NYHA class [-1.2 vs. -1.3 (mean), both P < 0.0001), 6 min walking distance [75.9 (P < 0.0001) vs. 46.4 (P = 0.0205) m], and quality of life scores [-25.2 vs. -18.7 (both P < 0.0001)] 1 year after implantation. Response rates using a combined clinical score (>or=1 NYHA classes or >or=25% increase in 6 min walking distance plus survival with freedom from heart failure hospitalizations for 1 year) were 73.2% and 75.4%, respectively (P = NS). There were reductions in left ventricular end-systolic volume [median of 20.3 mL (P = 0.0012) and 22.7 mL (P = 0.0066), respectively] and improvements in LVEF [median of 2.9% and 9.3%, respectively (both P < 0.0001)].
  
  
  CONCLUSIONS
  In patients with heart failure who are RV-paced, upgrading to CRT is associated with a similar long-term risk of mortality and morbidity to patients undergoing de novo CRT. Symptomatic improvements and degree of reverse remodelling are also comparable.
authors.affiliation: Department of Cardiology, University of Birmingham, Good Hope Hospital, Rectory Road, Sutton Coldfield, Birmingham, West Midlands B75 7RR, UK.
authors.forename: Paul W X
authors.initials: PW
authors.lastname: Foley
authors.forename: Sahrkaur A
authors.initials: SA
authors.lastname: Muhyaldeen
authors.forename: Shajil
authors.initials: S
authors.lastname: Chalil
authors.forename: Russell E A
authors.initials: RE
authors.lastname: Smith
authors.forename: John E
authors.initials: JE
authors.lastname: Sanderson
authors.forename: Francisco
authors.initials: F
authors.lastname: Leyva
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011446:Prospective Studies; D011788:Quality of Life; D012307:Risk Factors; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology; D018497:Ventricular Dysfunction, Right / Q000503:physiopathology*; D016138:Walking / Q000502:physiology