When a dog has a heart problem, diet is a large part of his treatment plan. Enhance your dog’s diet naturally with supplements and vitamins, such as Vitamin E, B-complex and chromium and selenium. Likewise, natural amino acids such as L-carnitine and taurine have been successful in helping dogs with congestive problems. L-carnitine aides the way a dog processes fat and energizes his heart. While taurine protects the heart from getting too much calcium and enhances the cell membranes.