Diet-Related Myocardial Failure in Dogs

Diet-Related Myocardial Failure in Dogs

July 23, 2018 (published)

Mark Rishniw; Paul Pion; Mark Kittleson on the Veterinary Information Network

Dilated cardiomyopathy (DCM) is one of the most common acquired heart diseases of medium to giant breed dogs. It occurs rarely in small breed dogs and cats. The disease is characterized by decreased contractility, with secondary, compensatory, ventricular dilation.¹

Clinical Signs: Ptients are typically asymptomatic until congestive heart failure or a serious arrhythmia (e.g. atrial fibrillation, ventricular tachycardia) is present. In one study, the most common signs and findings were increased respiratory rate and/or effort, cough, exercise intolerance, weakness, weak and/or irregular pulses, anorexia, auscultable murmur, weight loss, and fainting.³⁰ Depression, ascites, and a gallop sound occurred less often.³⁰ Occasionally, sudden death is the only clinical sign.

What is the latest information about myocardial failure and grain-free diets?

As of July 2018, several cardiologists have examined this issue and have not come to a single conclusion — some have implicated diets and taurine deficiency in specific breeds (e.g. Golden Retrievers) (Olsen 2018) (Morris Animal Foundation 2017), while others have shown a relationship between the implicated diets and DCM but failed to find a strong association with taurine deficiency (Adin et al 2018).

In July 2018, the FDA issued a warning that some diets might be associated with DCM. However, the association is far from established or clear. They issued an update to the original warning on 8/10/2018.

Which diets have been implicated?

Multiple diets have been implicated. One of the most common implicated diets is the Acana Pork and Squash Singles diet, although Nutrisource grain-free food has been mentioned as well. It is important to understand that any of the grain-free diets could be problematic (although there is currently no conclusive evidence that they are causal). In one study, Kangaroo and Red Lentil diet was implicated (Adin et al 2018). Therefore, rather than focusing on specific brands, clinicians should focus on the main ingredients in any “grain-free” diet. Clinicians should note that several companies manufacturing such diets have started to address the concerns by producing marketing literature and possibly changing diet composition, but this does not mean that a particular diet is “OK”. If it’s grain-free and legume-based, then it is considered a suspect diet.

What should I do if a client is feeding grain-free diets to their dog(s)?

There are several options that clinicians can consider, depending on the clinical presentation.

1. For dogs without cardiac clinical signs that appear healthy, changing the diet is the simplest and most conservative action until more definitive information relating to this emerging pattern is discerned.
2. If the owners do not wish to change the diet as a preventive measure without more information, consider an echocardiogram and testing taurine concentration in plasma and whole blood (see this link for sampling methods and submission requirements).
3. If myocardial failure is identified, change the diet and consider taurine supplementation regardless.
4. If taurine concentration is low, change the diet and initiate taurine supplementation
5. Repeat the echocardiogram in 4 to 6 months to assess resolution of the myocardial failure.
6. Report your findings to the FDA.
7. If the owners do not wish to change the diet or perform an echocardiogram, test the dog’s taurine concentration (plasma and/or whole blood).
   1. If low, supplement with taurine and strongly encourage changing diets to one not implicated in the problem.
   2. If normal, encourage the owners to keep abreast of evolving information on this issue.
8. If the owners are unwilling to change the diet and are unwilling or unable to afford an echocardiogram and taurine analysis, strongly encourage the owners to supplement the diet with taurine, which is safe and inexpensive.

How much taurine should I supplement? Can I overdose with taurine?

Safe doses of taurine are in the range of 250 mg per day for long-term supplementation. Acute dosing, in situations where a rapid correction is required are in the 500 mg to 1 gm per day range for most dogs (approximately 50 mg/kg/day). Whether large doses of taurine can cause problems is not well understood, but some researchers have raised concerns that long-term overdosing can cause problems. Therefore, high doses of taurine should be used only in cases where myocardial failure has been documented and only for 2-3 months, which myocardial function is being restored.

What resources are available for me and my clients?

• You can refer your clients to Lisa Freeman’s blog that discusses this issue in detail.
• The UC Davis website also has a page discussing the issue and the studies that are currently under way.

References

1) Simpson S, Edwards J, Ferguson-Mignan TFN, et al: Genetics of Human and Canine Dilated Cardiomyopathy. Int J Genomics 2015 Vol 0 (204823).

30) Martin MW, Stafford Johnson MJ, Celona B: Canine dilated cardiomyopathy: a retrospective study of signalment, presentation and clinical findings in 369 cases. J Small Anim Pract 2009 Vol 50 (1) pp. 23-29.

Proceedings

1. Adin D, DeFrancesco T, Keene B, Tou SB, Meurs K, Atkins CB, Aona BB, Kurtz KB, Barron LB. Echocardiographic Phenotype of Canine Dilated Cardiomyopathy Differs Based on Diet. ACVIM Forum 2018.

Rounds and Other Resources

1. Olsen J. Taurine Deficiency Induced Dilated Cardiomyopathy in Golden Retrievers. 2018
2. Morris Animal Foundation. Researchers getting closer to understanding dietary taurine and heart disease in dogs. 2017
3. Measuring Taurine — VIN Medical FAQ
4. How to report a pet food complaint to the FDA.