Dilated Cardiomyopathy (DCM) in Dogs – Diagnosis, Treatment, and Supplements

It’s been a year and a half since the FDA prematurely (and erroneously) blamed a rash of heart disease on grain-free dog foods. We’re no closer to the truth today, despite FDA’s “investigation” and a few hastily-researched papers in veterinary journals.

As of April 2019, there had been 560 dogs affected, and a handful of cats. (Yes, cats–even though taurine is already required to be added to foods intended as a cat’s sole source of nutrition.)

[For a detailed discussion of this issue, including implicated ingredients and brands, historical context, and updates, see Grain-Free Dog (and Cat) Food, Taurine, and Heart Disease]  

At this point, I want to provide guidance on what you might see if your dog (or cat) is developing DCM, and how to properly supplement taurine in case of potentially inadequate diets.

Unfortunately for cats (who are very good at hiding illness), by the time these signs are noticeable, there may be very little time to act–get your kitty to the vet right away!

Signs of DCM

  • Exercise intolerance/shortness of breath
  • Pale or purplish gums
  • Fast heart rate
  • Weak pulses
  • Coughing
  • Difficulty breathing
  • Weakness
  • Fatigue
  • Ataxia
  • Fainting
  • Consistently resting or sleeping sternally, or with the head/chest elevated
  • Constantly dilated pupils (uncommon in dogs, but a sign of blindness in cats)

Diagnosis of DCM

  • An ocular exam may show areas of thinning or holes in retinas. Although unusual in dogs, it may be an early warning sign in cats.
  • On exam, a fluid wave may be palpable in the abdomen; lungs may sound abnormal on auscultation.
  • Radiographs may show an enlarged heart, and if advanced, fluid buildup in lungs or abdomen.
  • Echocardiogram is definitive; it shows the heart muscle in real time.

NOTE: DCM is not uncommon in dogs; and in 70-80% of cases it has nothing to do with diet. To make that determination, your veterinarian must test for both whole blood and plasma taurine levels.

Treatment of DCM

Conventional medicines, including diuretics and medications to lower blood pressure and increase heart muscle contractility, may be necessary in cases of heart failure.

Supplementing with Taurine and Carnitine

While supplementing taurine is an obvious solution, it may also be beneficial to supplement L-carnitine, which affects taurine metabolism. Carnitine does not survive processing, and because it’s expensive, manufacturers rarely add it back.

Keep in mind that dogs with low taurine and DCM may or may not respond to supplementation. Building up to normal levels may take weeks to months.

One research paper indicated that dogs eating low-protein diets, such as those made for dogs with kidney disease, may be more likely to develop taurine deficiency and DCM, so it may be well worth it to supplement those dogs even if no signs are present.


  • Dogs with KNOWN taurine deficiency — 400 mg twice per day per 40s lb body weight
  • Dogs eating low-protein (renal) diets — 400 mg twice per day per 40s lb body weight
  • Healthy dogs under 50lbs — 500 mg of taurine twice per days
  • Healthy dogs over 50lbs — 1000 mg of taurine twice per day
  • Cats — 250 mg taurine per day


  • Dogs without DCM – L-carnitine 375 mg per 40 lbs body weight every 8 hours
  • Small-medium sized dogs with DCM – L-carnitine 500-1000 mg every 8 hours
  • Large dogs with DCM – L-carnitine 2000 mg every 8 hours

Carnitine is best given with food.

Recommended Brands

Tested taurine supplements that were within 5% of stated contents and, if applicable, tablet disintegrated within 30 minutes*

  • Mega-taurine caps by Twinlab (1000mg capsule)
  • Taurine by Swanson Health Products (500mg capsule)
  • Taurine by NOW foods (500mg capsule)
  • Taurine 500 by GNC (500mg tablet)

Tested L-carnitine supplements that were within 5% of stated contents and, if applicable, tablet disintegrated within 30 minutes*

  • L-carnitine 500 by Jarrow Formulas (500mg capsule)
  • L-carnitine caps by Country Life (500mg capsule)
  • Maxi L-carnitine by Solgar Vitamin and Herb (500mg tablet)
  • L-carnitine by Puritan’s Pride (500mg tablet)

*As tested by ConsumerLab.com

For more–perhaps too much–information, see Grain-Free Dog (and Cat) Food, Taurine, and Heart Disease!

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