Considering that the various monocyte subsets produce TNF-α, IL-6, IL-1β and that these inflammatory cytokines are important markers of active disease and HF prognosis [51], our study shows that CRT does not modulate the pro-inflammatory capacity of these cells, which may compromise the long-term response to CRT and even the overall survival of patients. The gene discussed is IL1B; the disease is hydrops fetalis.