title: Effect of low-amplitude two-dimensional radial strain at left ventricular pacing sites on response to cardiac resynchronization therapy.
abstract: BACKGROUND
  Left ventricular (LV) lead placement to areas of scar has detrimental effects on response to cardiac resynchronization therapy (CRT). Speckle-tracking radial two-dimensional strain offers assessment of the extent of regional myocardial deformation. The aim of this study was to assess the impact of LV lead placement at areas of low-amplitude strain on CRT response.
  
  
  METHODS
  The optimal cutoff of radial strain amplitude at the LV pacing site associated with an unfavorable CRT response was determined in a derivation group (n = 65) and then tested in a second consecutive validation group (n = 75) of patients with heart failure. Patients had concordant LV leads if placed at the most delayed site, and dyssynchrony was defined as anteroseptal to posterior delay ≥ 130 msec. CRT response was defined as a ≥15% reduction in LV end-systolic volume at 6 months.
  
  
  RESULTS
  In the derivation group, a derived cutoff for radial strain amplitude of <9.8% defined low-amplitude segments (LAS) and had a high specificity but low sensitivity for predicting LV reverse remodeling, suggesting a strong negative predictive value. In the validation group, compared with patients without LAS at the LV pacing site, in patients with LAS (n = 16), CRT response was significantly lower (62.7% vs 31.3%, P < .05). By multivariate analysis, LV lead concordance and the absence of an LAS at the LV pacing site but not dyssynchrony were significantly related to CRT response.
  
  
  CONCLUSIONS
  LV lead placement over segments with two-dimensional radial strain amplitudes <9.8% is associated with poor outcomes of CRT.
authors.affiliation: Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Fakhar Zaman
authors.initials: FZ
authors.lastname: Khan
authors.forename: Munmohan Singh
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: Denis
authors.initials: D
authors.lastname: O'Halloran
authors.forename: Michael
authors.initials: M
authors.lastname: Fahey
authors.forename: Maros
authors.initials: M
authors.lastname: Elsik
authors.forename: David
authors.initials: D
authors.lastname: Begley
authors.forename: Simon Patrick
authors.initials: SP
authors.lastname: Fynn
authors.forename: David Paul
authors.initials: DP
authors.lastname: Dutka
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D015331:Cohort Studies; D016001:Confidence Intervals; D004452:Echocardiography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D016017:Odds Ratio; D010138:Pacemaker, Artificial; D018570:Risk Assessment; D012720:Severity of Illness Index; D012737:Sex Factors; D013318:Stroke Volume / Q000502:physiology; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D020257:Ventricular Remodeling / Q000502:physiology