title: Cardiac resynchronization therapy in pacemaker-dependent patients with left ventricular dysfunction.
abstract: OBJECTIVE
  Heart failure and left ventricular (LV) systolic dysfunction (LVSD) are common in patients with permanent pacemakers. The aim was to determine if cardiac resynchronization therapy (CRT) at the time of pulse generator replacement (PGR) is of benefit in patients with unavoidable RV pacing and LVSD.
  
  
  RESULTS
  Fifty patients with unavoidable RV pacing, LVSD, and mild or no symptoms of heart failure, listed for PGR were randomized 1 : 1 to either standard RV-PGR (comparator) or CRT. The primary endpoint was the difference in change in LV ejection fraction (LVEF) between RV-PGR and CRT groups from baseline to 6 months. Secondary endpoints included peak oxygen consumption, quality of life, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels. At 6 months there was a difference in change in median (interquartile range) LVEF [9 (6-12) vs. -1.5 (-4.5 to -0.8)%; P < 0.0001] between the CRT and RV-PGR arms. There were also improvements in exercise capacity (P = 0.007), quality of life (P = 0.03), and NT-proBNP (P = 0.007) in those randomized to CRT. After 809 (729-880) days, 17 patients had died or been hospitalized (6 in CRT group and 11 in the comparator RV-PGR group) and two patients in the RV-PGR arm had required CRT for deteriorating heart failure. Patients with standard RV-PGR had more days in hospital during follow-up than those in the CRT group [4 (2-7) vs. 11 (6-16) days; P = 0.047].
  
  
  CONCLUSIONS
  Performing CRT in pacemaker patients with unavoidable RV pacing and LVSD but without severe symptoms of heart failure, at the time of PGR, improves cardiac function, exercise capacity, quality of life, and NT-pro-BNP levels.
authors.affiliation: Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health and Therapeutics, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Clarendon Way, Leeds LS2 9JT, UK.
authors.forename: John
authors.initials: J
authors.lastname: Gierula
authors.forename: Richard M
authors.initials: RM
authors.lastname: Cubbon
authors.forename: Haqeel A
authors.initials: HA
authors.lastname: Jamil
authors.forename: Rowenna
authors.initials: R
authors.lastname: Byrom
authors.forename: Paul D
authors.initials: PD
authors.lastname: Baxter
authors.forename: Sue
authors.initials: S
authors.lastname: Pavitt
authors.forename: Mark S
authors.initials: MS
authors.lastname: Gilthorpe
authors.forename: Jenny
authors.initials: J
authors.lastname: Hewison
authors.forename: Mark T
authors.initials: MT
authors.lastname: Kearney
authors.forename: Klaus K A
authors.initials: KK
authors.lastname: Witte
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D058406:Cardiac Resynchronization Therapy / Q000191:economics; D003362:Cost-Benefit Analysis; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010138:Pacemaker, Artificial / Q000191:economics; D010446:Peptide Fragments / Q000097:blood; D011788:Quality of Life; D012189:Retrospective Studies; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000503:physiopathology / Q000628:therapy*
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain
keywords: Heart failure; Left ventricular dysfunction; Pacemaker