Vitamin D levels predict the response to cardiac resynchronization therapy in patients with systolic heart failure

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 vs 21.15±5.9; 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).

CONCLUSION
In the present study, preimplantation level of vitamin D was found to be predictor of response to CRT, independent of BNP.