I have a 5 pound Chihuahua that is 13 years old and she currently has a grade 5 to 6 heart murmur, enlarged heart and enlarged left atrial and mitral valve disease. She is not in heart failure and her resting heart rate ranges from 18 to 20. She saw the cardiologist today for an echocardiogram and she has been taking Vetmedin and Ubiquinol for about 4 months now prescribed by her regular vet. It is taken a while to get her in to see this cardiologist He wants me to add spirolactone but she doesn’t have fluid or high blood pressure. He says he’d like to add this just to keep her from going into heart failure as a preventative. please give me your opinion if you think this is a good idea I’ve been reading conflicting stories that they shouldn’t go on a diuretic if they don’t have fluid. thanks so much! This is Chica!
Dr. Steve's Advice - Chica is very cute, Tracy Leath Broughton! I looked into the spironolactone, but cardiologists disagree whether it can do anything to halt progression in heart disease. It's considered a weaker but safer cousin of Lasix, and it can't prevent progression either.
That does not mean you're helpless, though. The heart findings signal a backing up of blood into the left side of the heart, and your cardiologist is worried it will progress from there into the lungs, causing pulmonary edema. There are two main causes to that kind of back pressure problem: (1) the vessels the heart is pumping into are too constricted; and (2) the heart is remodeling and dilating, such that the valves don't close properly anymore, impairing its ability to pump blood out of it.
Regarding the former issue, that is called endothelial dysfunction, and a JAVMA study in 2012 found it present in every dog with congestive heart disease that they checked. This manifests as hypertension when it's more severe. Some cardiologists have speculated you can prevent things progressing to hypertension by using spironolactone, but most now do not agree it won't. That's not a big surprise, because the problem is often diet. It's hard for a few mgs of a drug to counteract the pounds of food that dog's eat each day.
The first thing you can do that will work better than spironolactone is to change your dog's diet to a real food diet, if you haven't done so. The cause of the vessel narrowing problem known as endothelial dysfunction is a diet that raises insulin levels too easily and then keeps them high, because the diet is too easily absorbed. In other words, too processed. If your dog eats real food, then it is broken down much more slowly, insulin levels stay relatively low, and the condition eventually reverses. That means the heart can pump and empty itself more easily.
Problem 2 is interesting. Most veterinarians probably believe that the heart just passively dilates as blood accumulates inside it, stretching it out. Studies have shown that the process is active, however, mediated by a compound called calcineurin, and that if you inhibit that compound, the heart can remodel back to normal. I've seen this many times in clinical practice, as evidenced by a reversal of changes seen in previous echocardiograms. It has also been confirmed in laboratory studies.
The Chinese herbal formula called Minor Bupleurum contains compounds that inhibit calcineurin. Meanwhile, it counteracts endothelial dysfunction. You can obtain it as Harmonize the Qi from Kan Essentials (sometimes online) or from Natural Path (via your vet) as Xiao Chai Hu Tang (Minor Bupleurum). I usually pair it with another Kan Essentials formula called Blood's Palace, sold as Xue Fu Zhu Yu Tang (Persica and Carthamus) from Natural Path. Likewise, it counters endothelial dysfunction and helps support renal perfusion to prevent development of full on hypertension.
These two formulas should do what your cardiologist is looking for, especially if you change the food to a real food diet. I would not be surprised if the murmur starts to fade in intensity down to a 3 or 4 out of 6 after a few months on this protocol. Hopefully that helps you out!
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