title: The interaction of interventricular pacing intervals and left ventricular lead position during temporary biventricular pacing evaluated by tissue Doppler imaging.
abstract: OBJECTIVE
  To determine the effects of interventricular pacing interval and left ventricular (LV) pacing site on ventricular dyssynchrony and function at baseline and during biventricular pacing, using tissue Doppler imaging.
  
  
  METHODS
  Using an angioplasty wire to pace the left ventricle, 20 patients with heart failure and left bundle branch block underwent temporary biventricular pacing from lateral (n = 20) and inferior (n = 10) LV sites at five interventricular pacing intervals: +80, +40, synchronous, -40, and -80 ms.
  
  
  RESULTS
  LV ejection fraction (EF) increased (mean (SD) from 18 (8)% to 26 (10)% (p = 0.016) and global mechanical dyssynchrony decreased from 187 (91) ms to 97 (63) ms (p = 0.0004) with synchronous biventricular pacing compared to unpaced baseline. Sequential pacing with LV preactivation produced incremental improvements in EF and global mechanical dyssynchrony (p<0.0001 and p = 0.0026, respectively), primarily as a result of reductions in inter-LV-RV dyssynchrony (p = 0.0001) rather than intra-LV dyssynchrony (NS). Results of biventricular pacing from an inferior or lateral LV site were comparable (for example, synchronous biventricular pacing, global mechanical dyssynchrony: lateral LV site, 97 (63) ms; inferior LV site, 104 (41) ms (NS); EF: lateral LV site, 26 (10)%; inferior LV site, 27 (10)% (NS)). ECG morphology was identical during biventricular pacing through an angioplasty wire and a permanent lead.
  
  
  CONCLUSIONS
  Sequential biventricular pacing with LV preactivation most often optimises LV synchrony and EF. An inferior LV site offers a good alternative to a lateral site. Pacing through an angioplasty wire may be useful in assessing the acute effects of pacing.
authors.affiliation: International Centre for Circulatory Health, St Mary's Hospital and Imperial College, London, UK. rebecca.lane@imperial.ac.uk
authors.forename: R E
authors.initials: RE
authors.lastname: Lane
authors.forename: A W C
authors.initials: AW
authors.lastname: Chow
authors.forename: J
authors.initials: J
authors.lastname: Mayet
authors.forename: D P
authors.initials: DP
authors.lastname: Francis
authors.forename: N S
authors.initials: NS
authors.lastname: Peters
authors.forename: R J
authors.initials: RJ
authors.lastname: Schilling
authors.forename: D W
authors.initials: DW
authors.lastname: Davies
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017130:Angioplasty / Q000295:instrumentation; D002037:Bundle-Branch Block / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D015150:Echocardiography, Doppler / Q000379:methods; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013318:Stroke Volume; D013599:Systole; D016277:Ventricular Function, Left