title: Vitamin D levels predict the response to cardiac resynchronization therapy in patients with systolic heart failure.
abstract: OBJECTIVE
  The aim of this study was to examine the relationship between vitamin D levels in patients with heart failure (HF) and response to cardiac resynchronization therapy (CRT).
  
  
  METHODS
  We studied 57 patients (mean age: 60.47±13.09 years) with New York Heart Association Class II or III heart failure, QRS duration ?120 milliseconds, and ejection fraction <35% (mean: 27.1±4.4%) who underwent CRT. All patients were taking optimal medical treatment for HF. Patients were classified as CRT responders if they had >15% decrease in left ventricular end-systolic volume at 6 months compared with baseline measurements. Vitamin D levels were evaluated before CRT implantation with ELISA.
  
  
  RESULTS
  Of the 57 patients, 34 patients (59.6%) were classified as responders and 23 patients (40.4%) were classified as non-responders. Baseline features, laboratory findings, and echocardiographic characteristics were nearly the same in both groups. High vitamin D level was detected in responder group compared to non-responder group (26.17±7.5 ng/mL vs 21.15±5.9 ng/mL; p=0.009). Age, hypertension, diabetes mellitus, ischemic cardiomyopathy, QRS morphology and duration, and levels of B-type natriuretic peptide (BNP) and vitamin D were associated with CRT response in our study population. In multivariate regression analysis, preimplantation QRS duration, and BNP and vitamin D levels remained independent predictors (QRS duration Odds ratio [OR]: 1.047, CI: 1.019-1.417, p=0.006; BNP OR: 0.997, 95% CI: 0.994-0.999, p=0.029; vitamin D OR: 1.121, 95% CI: 1.011-1.242, p=0.030).
  
  
  CONCLUSIONS
  In the present study, preimplantation level of vitamin D was found to be predictor of response to CRT.
authors.affiliation: Department of Cardiology, Dışkapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey. hamzasunman@gmail.com.
authors.forename: Hamza
authors.initials: H
authors.lastname: Sunman
authors.forename: Adem
authors.initials: A
authors.lastname: Özkan
authors.forename: Hikmet
authors.initials: H
authors.lastname: Yorgun
authors.forename: Uğur
authors.initials: U
authors.lastname: Canpolat
authors.forename: Naresh
authors.initials: N
authors.lastname: Maharjan
authors.forename: Serkan
authors.initials: S
authors.lastname: Asil
authors.forename: Ergün Barış
authors.initials: EB
authors.lastname: Kaya
authors.forename: Tülin
authors.initials: T
authors.lastname: Bayrak
authors.forename: Lale
authors.initials: L
authors.lastname: Tokgözoğlu
authors.forename: Asuman
authors.initials: A
authors.lastname: Özkara
authors.forename: Kudret
authors.initials: K
authors.lastname: Aytemir
authors.forename: Ali
authors.initials: A
authors.lastname: Oto
mesh_terms: D015415:Biomarkers / Q000097:blood; D058406:Cardiac Resynchronization Therapy; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000097:blood / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D013599:Systole; D016896:Treatment Outcome; D014807:Vitamin D / Q000097:blood*
chemical_list: D015415:Biomarkers; D014807:Vitamin D