Athletes can develop an enlarged heart as a result of prolonged physical training that makes the heart stronger and healthier. However, a heart that becomes enlarged in a sedentary person is a symptom of beri beri, an advanced thiamine (vitamin B-1) deficiency, and may result in heart failure. Selenium and L-carnitine help to strengthen heart tissue.
See also the book, BYPASS THE BYPASS: Restore Circulation Without Surgery (available at Amazon.com)
Example of a cardiovascular nutrition formula: https://vitamost.club/products/rtre-cardiovascular-nutrition-vitalized