Here are some links that you may find helpful in making the right decision for your puppy and yourself.
http://www.caninehearthealth.com/
http://www.carnitine-taurine.com/
http://www.upei.ca/~cidd/Diseases/cardiovascular%20diseases/PDA.htm
Please let me know how you make out. Hopefully some other experts will be able to shed some light on this for you.
In the meantime, I will see if I can come up with anything that will be useful.
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Peace and happiness to you and your pet! ~ Christina
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