(A) Two principle coordinates are plotted, derived from the Bray-Curtis measure of beta diversity, summarizing similarity of gut microbial communities across patient categories. PCoA 1 explains 5.3% and PCoA 2 explains 3.7% of variation in microbial communities. p-value derived from PERMANOVA Adonis test of any difference across category = 0.09. (B) Means values of the first principle coordinate derived from the Bray-Curtis measure of beta diversity across patient category. Light bars: unadjusted. Dark bars: adjusted for age, sex, race/ethnicity, and antibiotic use. p-value for any difference across patient category <0.0001. The p-value for linear trend among patients with HF < 0.0001. HF, heart failure; HT, heart transplantation, LVAD, left ventricular assist device; PCoA, principal coordinates analysis; PERMANOVA, permutational multivariate analysis of variance.