Dogs with big hearts.

We’ve all heard someone speak of someone being "big-hearted", or "having a lot of heart".  Those are good things.  Having a truly big heart (as in enlarged) is not a good thing.

Patients who have abnormally large hearts don’t generally have a nice big, strong heart.  They usually have weak, flabby, stretched out of shape hearts.  When you see an enlarged heart silhouette on a chest X-ray, you really don’t know what is making that big shadow (other than that it’s heart-related).

It could be a really big, thick-walled muscular heart with almost no chamber in the middle.  That’s called hypertrophic cardiomyopathy (a heart muscle excessively developed in size to the point of disease).  Of course, you probably won’t be seeing that on a chest X-ray.  We usually X-ray the chest when the animal is having some difficulty that suggests heart or lung problems.  If you have this disease, most patients feel pretty good until one day sudden death occurs.  It’s often a post-mortem diagnosis.

Sometimes the large heart shadow on the X-ray is misleading. The heart is of normal size, but the pericardial sac that surrounds it has become enlarged with an accumulation of fluid.  The heart is normally surrounded by a small, tough membranous sac with a tiny amount of fluid to protect it from friction as it moves around in the chest.  Various diseases can cause the sac to become filled with blood, with fluid, with tumors.  It can become so filled with fluid around the heart that it compresses the heart and makes it difficult for it to fill and to function as a pump.

Most commonly, we find a thin-walled, flabby-muscled, stretched out of shape, weak heart.  This is what we see in congestive heart failure.  Either side or both sides may be affected.   Right heart failure causes blood to back up in the  liver and abdomen, with consequent swelling and damage of the liver, and the seeping of fluid into the belly.  Left heart failure causes blood to back up in the lungs, with fluid seeping into the lungs.  The most common early signs are poor endurance and coughing after exercise.  This coughing can occur because of the fluid in the lungs.  Eventually all the organs suffer because of their poor circulation.  Some patients have fainting spells because their weak heart can’t get oxygen to their brains and their muscles at the same time.

Another cause of cough is a heart that is just so big that it is actually putting pressure on the windpipe and bronchial tubes, just like someone putting your neck in a choke-hold.  You take a chest X-ray and the heart looks like a basketball.  All of the other situations can usually be mitigated with medicines that reduce the heart’s workload or strengthen its efforts.  With a heart this big, you don’t have a lot of alternatives; sometimes you wind up being reduced to trying cough suppressants.  When that doesn’t work, you’ve run out your string.  He can’t get comfortable, he can’t rest, it’s hard to breathe, and he coughs all the time.  It’s pretty tough to look at a patient with no quality of life because his own heart is squashing his airway.

Most of my heart patients can be helped a lot, but this particular patient left me with nothing in hand but a final release.  Makes you feel like the Wizard of Oz when Dorothy says, "I don’t think there’s anything in that bag for me, is there?" 

Coming soon: the ways we can help most of our congestive heart failure patients.

3 thoughts on “Dogs with big hearts.

  1. Doc says:

    Hello, Mr. Hawkns,

    I am sorry to hear about your situation. It’s always tough to come to the end of the line. None of have so many friends that we are anxious to lose one.

    Sometimes we have to look at how many good days we have versus bad days. Also look at the things your dog enjoys and see if he is still able to enjoy them.

    Another way to look at things is how much the situation can be improved with treatment. Sometimes the answer is “not much”, and that’s a bad thing to have to tell someone.

    Best wishes at this difficult time.

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