Repost on February 5, 2023.
"Your average thoroughbred race horse has a heart that weighs about seven pounds. There is, however, a specific gene, this gene is actually called "the X-factor" and it passed down maternally, that results in oversized hearts in race horses. The bigger the horse's heart, the faster and longer it can run. Before Secretariat, a "superhorse" (yes, they actually use that term too) with the X-factor gene could end up with a heart weighing around thirteen or fourteen pounds. To say that a horse with a fourteen pound heart can outrun the heck out of a horse with a seven-pound heart is kind of an understatement. That's why these horses are called "superhorses" without a trace of irony in the racing community.
It turns out that Secretariat had the mutant X-gene too. After Secretariat's death and autopsy in 1989, it was found that the weight of his heart was either 21 or 22 pounds, depending on which source you believe. That is three times the weight of the average thoroughbred's heart. (I will continue to pray into this and ask more of the Holy Spirit as to what is being shown to us through these horses) - Annamarie"
src: Victory Coach Annamarie Strawhand on YouTube.com