Until the exact cause of DCM is known I would not feed any foods containing peas, lentils, other legume seeds, or potatoes/sweet potatoes that are listed in the first 5 ingredients.
The U.S. Food and Drug Administration has issued an alert about reports of canine dilated cardiomyopathy (DCM) in dogs eating pet foods containing peas, lentils, other legume seeds, or potatoes as main ingredients. “These reports are unusual because DCM is occurring in breeds not typically genetically prone to the disease.” DCM is a disease of the heart muscle and results in an enlarged heart that often results in congestive heart failure.
“Breeds that are typically more frequently affected by DCM include large and giant breed dogs, such as Great Danes, Boxers, Newfoundlands, Irish Wolfhounds, Saint Bernards and Doberman Pinschers. It is less common in small and medium breed dogs, except American and English Cocker Spaniels. However, the cases that have been reported to the FDA have included Golden and Labrador Retrievers, Whippets, a Shih Tzu, a Bulldog and Miniature Schnauzers, as well as mixed breeds.”
“Diets in cases reported to the FDA frequently listed potatoes or multiple legumes such as peas, lentils, other pulses (seeds of legumes), and their protein, starch and fiber derivatives early in the ingredient list, indicating that they are main ingredients. Early reports from the veterinary cardiology community indicate that the dogs consistently ate these foods as their primary source of nutrition for months to years.” https://www.petfoodindustry.com/articles/7984-infographic-official-data-on-grain-free-dog-food-and-dcm
Diseases of the heart and lungs — One of the symptoms of a heart condition such as dilated cardiomyopathy in dogs is excessive panting.
What do we know?
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Foods eaten by members’ dogs with DCM (list of popular foods)
“Taurine deficiency is well-documented as potentially leading to DCM.” This was a problem with cats in the 1980s. Cats require taurine in their food and it is considered essential in their diet. Taurine has not been considered essential for dogs since they can synthesize taurine from the amino acids cysteine and methionine. The FDA issued their alert after a significant number of dogs developed DCM that were on foods containing high levels of peas, lentils, legumes, or potatoes. These dogs were found to have low levels of taurine in their blood. The exact cause is not known and is currently being studied. It may be that certain dogs have a higher requirement for taurine in their diets. The cause may be low or poor quality proteins in the diet, or be caused by ingredient interactions. DCM in dogs has been studied for years although the cause is not certain there have been low taurine levels in dogs that are associated with lamb meal and rice foods, rice bran, cellulose, beet pulp, and high fiber diets.
“Unfortunately, some processed pet food advocates are using the link between grain-free dog foods and DCM to try to push pet parents back in the direction of grain-based diets. Don't be fooled. The problem with grain-free formulas isn't the lack of grains!”
“Taurine is found naturally in animal-based proteins; so, providing diets that include a sufficient level of high-quality animal proteins ensures adequate taurine intake.” 
“Taurine is present primarily in animal tissues, with greatest concentrations found in muscle tissue. Seafoods provide the most concentrated source (³1000 mg/kg of dry weight), and poultry also contains high levels. 80 Although a carnivorous diet ensures the cat an adequate taurine intake, the consumption of a diet containing high amounts of plant products and cereal grains may not provide sufficient taurine.” 
“Given what we do know, a recommendation is to feed a food that contains sufficient levels high quality, animal-source protein, does not include plant-source proteins as its primary protein source, and does not contain high levels of dietary fiber.”
Linda Case - dog trainer, canine nutritionist and science writer who specializes in topics about dog training, behavior and nutrition.
In mid-July, the U.S. Food and Drug Administration (FDA) released an alert to veterinarians and pet owners regarding reports of increased incidence of a heart disease called canine dilated cardiomyopathy (DCM). This disorder is characterized by weakening of the heart muscle, which leads to a decreased ability of the heart to pump, and if untreated, to cardiac failure. The reported cases occurred in breeds that are not considered to be genetically predisposed to this disorder.
By Dr. Karen Shaw Becker
Until we have much more information on the subject, my current recommendation is to supplement all dogs with high-taurine foods, no matter what type of diet they're eating. An easy way to do this is to simply mix a can of sardines into your pet's meal once a week.
The association between pulse ingredients and canine dilated cardiomyopathy: addressing the knowledge gaps before establishing causation
Dr. Josh Stern, a veterinary cardiologist and geneticist at UC Davis School of Veterinary Medicine, began seeing an alarming trend in cases at the veterinary hospital two years ago.
High Taurine foods (page 2)
Studies on canine dilated cardiomyopathy
Idiopathic dilated cardiomyopathy in Dalmatians: nine cases (1990-1995) - Journal of the American Veterinary Medical Association, 1996
Dietary rice bran decreases plasma and whole-blood taurine in cats - The Journal of Nutrition, 2002
Taurine deficiency in dogs with dilated cardiomyopathy: 12 cases (1997-2001) - Journal of the American Veterinary Medical Association, 2003
Taurine status in normal dogs fed a commercial diet associated with taurine deficiency and dilated cardiomyopathy - Journal of Animal Physiology and Animal Nutrition, 2003
Plasma and whole blood taurine in normal dogs of varying size fed commercially prepared food Journal of Animal Physiology and Animal Nutrition 2003
Taurine-deficient dilated cardiomyopathy in a family of golden retrievers - Journal of the American Animal Hospital Association, 2005
Dietary beet pulp decreases taurine status in dogs fed low protein diet – Journal of Animal Science and Technology, 2016