Researchers from Italy demonstrated that the higher the level of candida and pathogenic bacteria present in the intestinal tract, the greater the risk of chronic heart failure. Of those people studied, 100% of them had increased intestinal permeability, which allows these microbes to spread more easily throughout the body.
"The subgroup of moderate-severe CHF patients had significantly greater development rates of candida, campylobacter, and shigella compared with the subgroup with mild CHF. They also had greater intestinal permeability." http://www.medscape.com/viewarticle/856123
With gluten as a cause of increased intestinal permeability, it makes sense that those with heart risk should avoid gluten, as well, as gluten increases intestinal permeability.