title: Impact of VV optimization in relation to left ventricular lead position: an acute haemodynamic study.
abstract: OBJECTIVE
  Left ventricular (LV) lead placement to the most delayed segment offers the greatest potential benefit to cardiac resynchronization therapy (CRT). We assessed the impact of interventricular (VV) optimization on acute changes in cardiac output (CO) in patients with and without LV pacing of the most delayed segment.
  
  
  RESULTS
  In 124 patients, the most delayed segment was defined by speckle tracking radial strain and the LV lead position by biplane fluoroscopy. Patients were classified as either a concordant (LV lead at latest site), adjacent (within one segment), or remote (two or more segments away) LV lead. Atrioventricular (AV) and VV delays were optimized by echocardiography. Cardiac output was measured non-invasively and a >20% increase in CO from baseline (intrinsic) defined acute response. Changes in CO in patients with concordant, adjacent, or remote LV leads were recorded following atrioventricular optimization alone (AV OPT) and after combined AV and VV optimization (AV/VV OPT). Compared with AV OPT pacing, AV/VV OPT produced a greater rise in CO (5.45 ± 1.1 vs. 5.76 ± 1.2 L/min, P< 0.001) and higher acute response rates (48.4 vs. 61.3%, P= 0.041). In adjacent patients, compared with AV OPT pacing, AV/VV OPT settings increased the response rate from 36.4 to 63.6% (P= 0.037). VV optimization had no effect on acute response rates in patients with remote (26.7 vs. 33.3%, P = 0.581) or concordant LV leads (65.6 vs. 72.1%, P = 0.438).
  
  
  CONCLUSIONS
  VV optimization overcomes some but not all of the deleterious effects of a suboptimal LV lead position.
authors.affiliation: Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK.
authors.forename: Fakhar Z
authors.initials: FZ
authors.lastname: Khan
authors.forename: Munmohan S
authors.initials: MS
authors.lastname: Virdee
authors.forename: Philip A
authors.initials: PA
authors.lastname: Read
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Pugh
authors.forename: David
authors.initials: D
authors.lastname: Begley
authors.forename: Simon P
authors.initials: SP
authors.lastname: Fynn
authors.forename: David P
authors.initials: DP
authors.lastname: Dutka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000628:therapy*; D002302:Cardiac Output / Q000502:physiology; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D004452:Echocardiography; D004566:Electrodes; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000628:therapy*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000628:therapy*