title: Longer right to left ventricular activation delay at cardiac resynchronization therapy implantation is associated with improved clinical outcome in left bundle branch block patients.
abstract: Data on longer right to left ventricular activation delay (RV-LV AD) predicting clinical outcome after cardiac resynchronization therapy (CRT) by left bundle branch block (LBBB) are limited. We aimed to evaluate the impact of RV-LV AD on N-terminal pro-B-type natriuretic peptide (NT-proBNP), ejection fraction (EF), and clinical outcome in patients implanted with CRT, stratified by LBBB at baseline.
  
  
  
  Heart failure (HF) patients undergoing CRT implantation with EF ≤ 35% and QRS ≥ 120 ms were evaluated based on their RV-LV AD at implantation. Baseline and 6-month clinical parameters, EF, and NT-proBNP values were assessed. The primary endpoint was HF or death, the secondary endpoint was all-cause mortality. A total of 125 patients with CRT were studied, 62% had LBBB. During the median follow-up of 2.2 years, 44 (35%) patients had HF/death, 36 (29%) patients died. Patients with RV-LV AD ≥ 86 ms (lower quartile) had significantly lower risk of HF/death [hazard ratio (HR): 0.44; 95% confidence interval (95% CI): 0.23-0.82; P = 0.001] and all-cause mortality (HR: 0.48; 95% CI: 0.23-1.00; P = 0.05), compared with those with RV-LV AD < 86 ms. Patients with RV-LV AD ≥ 86 ms and LBBB showed the greatest improvement in EF (28-36%; P<0.001), NT-proBNP (2771-1216 ng/mL; P < 0.001), and they had better HF-free survival (HR: 0.23, 95% CI: 0.11-0.49, P < 0.001) and overall survival (HR: 0.35, 95% CI: 0.16-0.75; P = 0.007). There was no difference in outcome by RV-LV AD in non-LBBB patients.
  
  
  
  Left bundle branch block patients with longer RV-LV activation delay at CRT implantation had greater improvement in NT-proBNP, EF, and significantly better clinical outcome.
authors.affiliation: Heart and Vascular Center, Semmelweis University, Varosmajor 68, Budapest H-1122, Hungary.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Kosztin
authors.affiliation: Heart and Vascular Center, Semmelweis University, Varosmajor 68, Budapest H-1122, Hungary.
authors.forename: Valentina
authors.initials: V
authors.lastname: Kutyifa
authors.affiliation: Heart and Vascular Center, Semmelweis University, Varosmajor 68, Budapest H-1122, Hungary.
authors.forename: Vivien Klaudia
authors.initials: VK
authors.lastname: Nagy
authors.affiliation: Heart and Vascular Center, Semmelweis University, Varosmajor 68, Budapest H-1122, Hungary.
authors.forename: Laszlo
authors.initials: L
authors.lastname: Geller
authors.affiliation: Heart and Vascular Center, Semmelweis University, Varosmajor 68, Budapest H-1122, Hungary.
authors.forename: Endre
authors.initials: E
authors.lastname: Zima
authors.affiliation: Heart and Vascular Center, Semmelweis University, Varosmajor 68, Budapest H-1122, Hungary.
authors.forename: Levente
authors.initials: L
authors.lastname: Molnar
authors.affiliation: Heart and Vascular Center, Semmelweis University, Varosmajor 68, Budapest H-1122, Hungary.
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Szilagyi
authors.affiliation: Heart and Vascular Center, Semmelweis University, Varosmajor 68, Budapest H-1122, Hungary.
authors.forename: Emin Evren
authors.initials: EE
authors.lastname: Ozcan
authors.affiliation: Heart and Vascular Center, Semmelweis University, Varosmajor 68, Budapest H-1122, Hungary.
authors.forename: Gabor
authors.initials: G
authors.lastname: Szeplaki
authors.affiliation: Heart and Vascular Center, Semmelweis University, Varosmajor 68, Budapest H-1122, Hungary merkely.bela@kardio.sote.hu.
authors.forename: Bela
authors.initials: B
authors.lastname: Merkely
mesh_terms: D000200:Action Potentials; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D002908:Chronic Disease; D018572:Disease-Free Survival; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D011237:Predictive Value of Tests; D011446:Prospective Studies; D020127:Recovery of Function; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain
keywords: Cardiac resynchronization therapy response; Clinical response; RV-LV activation delay