Your Pet's Best Friend

Right-side Heart Failure and Ascites

Fluid accumulation in the abdominal cavity (around the organs) is called "ascites".  The old-timey name for it was "dropsy".  Right-sided heart failure can certainly cause it.  There are other things that can cause it, as well. 

Cancerous growths in the abdomen can secrete fluid.   The first sign of my mother's ovarian cancer was the fluid build-up.  Starvation can cause it.  The plasma protein albumin is a big molecule that helps hold fluid inside the blood vessels.  They seep fluid without it, which is why those starving refugee kids (that you quickly skip past when channel-surfing) have such big bellies.  Without protein, they can't make albumin; that big belly doesn't mean they just got their CARE package.  If your liver is failing, it can't use the protein you have to make albumin, so that's another possible cause of ascites.

Hemorrhage from a ruptured spleen or urine from a ruptured bladder may fill the abdomen with fluid, but you'd have a lot of other things going wrong as well.

Since heartworms reside mostly in the pulmonary arteries (taking blood through the lungs to get oxygen), they are the most common cause of right-side heart failure in dogs.  The arteries filled with worms create too much work for the heart to pump against, and it wears out from constant overwork.  It becomes enlarged because the weakened muscle gets "flabby" and stretches out of shape.  Now it can no longer contract forcefully, and blood that should be getting pumped forward gets backed up in the great veins returning blood to the heart from the rest of the body.

This back-pressure causes the veins to seep water like a canvas hose, and fluid accumulates in the abdominal cavity.  Ginny, here, does not have heartworms, but has (for unknown reasons) developed right-sided heart failure at a very young age.  She doesn't look too bad from the side view above, but she is carrying about three gallons of unwanted fluid on her abdomen.  From the top view you can get a better appreciation for the amount of abdominal enlargement she has. 

Medications can help the failing heart by decreasing its workload, such as diuretics (i.e. Lasix or furosemeide, spironolactone) to reduce fluid loading, and vasodilators (such as enalapril) to decrease the resistance in the blood vessels, and pushing the heart muscle a little harder (pimobendan, and the old standby digoxin).  Ginny is taking all of these, but it doesn't prevent the fluid build-up.  It's not too bad for a couple of weeks, but then she hits a "tipping point" and it balloons out of control.   We try to catch it before this point, but the big ice storm and two-week power-outage messed up our schedule. 

Here's Ginny with the bucket (literally) full of fluid that we just drained out of her. 

And here's a close-up.  The fluid looks clear when it is draining, but there are enough abdominal lining cells and blood cells present to make it look red when you have three gallons of it like this.

And here's Ginny, 24 pounds lighter, feeling good and looking a lot different.  Once that fluid is out, she feels pretty good.  She can't tolerate any strenuous exercise, but she has a good quality of life.  Pretty great for someone the cardiologist predicted would succumb by last October.  Her owner's devotion to getting all her meds on time, twice a day, every day has made the difference.  That and a few trips to the draining station.

Pericardial Effusion

This is Big Jake.  "When he lays around the house, he really lays around the house." [rim-shot!]  His 147 pounds are covering my exam table and slopping off the edge.  Five days ago he came in because he had been panting in the early morning.  He seemed to feel better by the time they came in, but he did seem to be favoring his left hind leg, and you could see where he had been licking it.  I couldn't find much, but we radiographed the foot (no mean feat, as he covers the X-ray table, too -- how to get him on the table, with his foot in the middle of the table, without the rest of Jake in the way?  Not to mention lifting him!)

So we sent him home with some anti-inflammatory/pain reliever and a little "wait and see".  He progressed to be more and more uncomfortable.  He panted more, couldn't get comfortable and quit eating.  It wasn't the medicine, because he refused to take that.  His owner noted that he was more uncomfortable lying down, and often resumed a sitting position to relieve his discomfort.  That "sitting up to get comfortable" is a hallmark of patients who are having breathing problems.  So, we asked her to bring him back in. [If you're wondering about the delay, the owner lives 60 miles away.  She doesn't just rush in on a moment's notice.]

His exam wasn't much different from the other day, and his lungs sounded okay.  The clinical signs and history still say something's wrong in his chest, and this is it.  His heart looks like a basketball.  I've talked about big hearts in a previous post.   Is it a stretched out of shape, weak, flabby heart?  A big, thickened, overly muscular heart?  A heart trapped in a pericardial sac full of fluid?  [A pericardial effusion is exactly that.] The ultrasound exam (echocardiogram) will tell us.  Of course, getting Big Jake in position was a logistical challenge[, but we finally got it done.  It's a big sac full of fluid, putting constant pressure on his heart, interfering with its function, making him hurt.

As with anything else on a dog this big, tapping and draining that sac was a pretty big project.  It was certainly more challenging than the case I had last fall.  We drained 600 cc (20 ounces) of fluid, giving him dramatic relief.  Unfortunately, he's going to need a chest surgery to remove that sac (and the heart-base tumor that we think is in it).  He feels better for now, though.

Kidney failure

Here’s a portrait of a nice, healthy kidney, but that’s not the kind we’re talking about. We are talking about pets with kidney failure. Does that mean "it’s over"? Maybe yes, maybe no. Kidney failure (or renal failure, as we scientific types like to say) can be acute or chronic. "Renal failure" means that the kidneys are not working well enough to clear waste from the bloodstream. We measure BUN, creatinine, and phosphorus levels (among other things). The patient may be producing lots of urine (or not), but when these wastes rise above normal levels, we know the kidneys aren’t working well.

BUN is Blood Urea Nitrogen, a waste-product that can fluctuate rapidly in the course of a day, being influenced even by how much you eat and drink. It still shouldn’t get much above 30. It can rise to double or triple that value, or even more. Creatinine levels change slowly, over a period of days, and phosphorus levels don’t start creeping up until the kidneys have really gone south.

This could be chronic -- the culmination of a long-standing, slow deterioration, and there is just not much functional kidney tissue left. Or it could be acute – the kidneys just suddenly got sick; they aren’t functioning, but they are not destroyed, either, and they could get well. Sometimes the only way to find out is to treat the patient and see if they respond.

You start out with about four times as much kidney capacity as you need. You could get by with half of one healthy kidney, and you have two whole ones. Thus, you could have a slow, gradual long-term destruction of the organs. Until you get down below 25% of kidney tissue, you still feel okay. Even when you get below 25%, your body can stand the increased levels of waste and become accustomed to them. When these guys finally get sick enough to quit eating, when they get nauseated and start throwing up, they are beyond saving. BUN is 100, other values up, and things don’t look good.

On the other hand, the kid whose kidneys shut down because of an infection will be just as sick, and his numbers may be just as bad. Yet, with appropriate treatment he could get well.

How do we know whether your pet’s kidney disease is acute or chronic? Can you tell by looking at the dog? This dog looks pretty good, beautiful hair coat, but she has lousy numbers – very high levels of waste in her blood. She looks awfully good, but her kidneys don’t look so good.

When we ultrasounded her kidneys, they looked shrunken and misshapen, as in this diagram. Her owners wanted to treat her, even though her prognosis didn’t look good. Intensive fluid and diuretic therapy were instituted, but she just did not respond. She couldn’t respond, as she just didn’t have the functional kidney tissue. Things won’t always be that clear-cut, though. Sometimes the kidneys really won’t look bad on the ultrasound, even though the damage may be severe and irreversible, whether chronic or acute.

This little dog doesn’t look nearly as healthy as the last one, and she is several years older, and she had lousy numbers when she came in.

Her ultrasound looked okay, but that was no guarantee. This is a sick kidney, but it hasn'treally changed shape.  This dog is a classic illustration of the principle that sometimes the only way to tell if a patient is treatable is to treat them. In this case, we also saw evidence of kidney infection in her urine specimen, so we hoped that intensive therapy with I.V. fluids and antibiotics might turn her around.

And so it did. Here she is the next day, feeling great, and eating, and she is still trucking along months later. If we had tried to "tell by looking", I’d have given her up. I’m glad we gave her our best.

Pyometra revisited

Warning: gross pictures at the bottom

I've posted on pyometra before, and also on why you should spay your dog while she's young and healthy.   Today we had a really spectacular case, though.  This  beautiful German Shepherd is only 2 years old, and had what appeared to be a normal heat cycle three weeks ago.  Yesterday she started having a bloody discharge.

Her clotting time was normal and she had plenty of platelets, so it didn't look like a "bleeding problem", despite the blood on the floor.  White blood cell count was really high (30,000/mm3, vs 7,000 to 16,000 normal range), and red blood cells were a little low.   An ultrasound of her uterus showed it to be huge.  How huge was it?

The normal uterus, even in a big dog like this, is about the size and weight of a couple of pencils.  This baby weighed over 4&1/2 pounds.

When we opened it, yes, it was full of pus. More than two liters of pus.  Man, do I ever wish this dog had been spayed a long time ago.  Did I mention I had to do the surgery on my afternoon off? Yeah.  The upside is, she's doing great now. Prognosis is good.

Heart failure and fluid accumulation

This is Toby with a blow-by oxygen tube in front of his face.  Toby is 14 years old.  As often happens, in the earlier stages of his disease a lot of his clinical signs were  chalked up to "just getting older".  When he began having difficulty breathing, his mom sought help.  This is a lady who loves her cats and is committed to their care, and it was quite a shock to see Toby with a belly full of fluid, swollen limbs, and seriously thin.  Part of this was his hair "filling in the gaps" early on, part of it was the gradual transition, and part of it was that "just getting older" thing.

Here's why he was having trouble breathing.  I'm sure it was a little difficult moving his diaphragm with that belly full of fluid, but having a chest full of fluid really made it hard.  His lungs are compressed down to about one-fourth of the space they usually occupy.  His heart cannot be seen here because it is obscured by the fluid around it.   An ultrasound examination showed that the right side of his heart was stretched out of shape, weak and flabby.  The inability of his heart to pump fluid forward was causing it to back up in the veins, and this back-pressure was causing the fluid to seep out of his veins and accumulate in his belly, chest and limbs.  His other organs were also suffering from poor circulation.

You can't really wait for medicine to take care of this, so we stayed late last Friday.   Thoracocentesis means sticking a needle (or in this case a flexible catheter tube) into the chest and draining off the fluid.  This was only about half the fluid in the chest, but it was all we could get without undue stress and trauma.  He was breathing much easier afterwards.

The next step was support with diuretics to help with the fluid reduction (which also reduces the heart's workload) and enalapril to further reduce the heart's workload.  He tolerated his medicine well, and has been eating well, but we aren't getting optimistic yet.  We may have to add more medicines to his program.  After his first week, his legs aren't swollen anymore, but his chest had refilled with fluid.  There was a little less fluid than last week, and we were able to remove about twice as much this time.

Toby is feeling halfway decent after the second round of drainage.  It's day by day now, and a consultation with a cardiologist.  Yeah, he's got a failing heart and he's 14 years old, but we're going to see if we can't give him some more good days.

My first pericardiocentesis.

Percardiocentesis - a big word.  You'll know what it means by the end of the post.

The phone rings at 6:00 AM.   "I didn't mean to wake you".  [How could I answer the phone if I weren't awake?] It turns out that Coco had had a tough night.  So had her folks.

I had seen her the day before. Coco is a little Poodle, around eleven years old, weighs 18 pounds, has always been pretty healthy.  She had come in for her annual check-up, no problems... well, she'd been coughing a little, and seemed to breathe heavily, but just in the last few days.  When we X-rayed her chest, her heart looked like a basketball.  Ultrasound (echocardiogram) revealed a normal heart inside a pericardial sac filled with fluid -- a LOT of fluid.  Coco's folks said that referral to the specialists in Memphis was out of the question.  When I consulted with the cardiologist by phone, he felt that since Coco wasn't in much distress, we didn't need to have the folks make an emergency trip back for drainage of the fluid.  "Don't wait 'til next week, though."   As it turned out, waiting overnight had been a bad idea.

Her breathing was much more labored this morning.  It was obvious that she would be moving to the front of the line.  The heart is normally surrounded by a membranous sac containing a small amount of fluid to lubricate the heart surface so that it's not rubbing on things as it beats.  This pericardial sac had to be drained.  In twenty-nine years of practice, it was my first time.  I've done similar procedures to remove fluid from the abdomen and chest, but poking around the heart is a bit more delicate.  There's a great description of "how to do it" in Ettinger's Textbook of Internal Medicine.  How'd you like to have your family doctor poke a big needle in your chest after "reading up on it a little"?  The cardiologist also gave me some pointers, and I had the ultrasound to help guide me.  It went fine, and after removing 5 ounces of fluid from around her heart, Coco immediately felt better.  She trotted out of the clinic like a puppy.

The bad news is, the source of the fluid is probably a tumor.  It's hard to say how soon the fluid will return, but we're pretty sure it will.  Even if her owners were up for a big exploratory chest surgery (and they are not), the outlook is pretty grim.  We'll just hope for some happy days in the meantime.

Unusual reactions to vaccines and other things

An idosyncratic reaction is a reaction that is peculiar to one individual (or at least to a very small minority of patients).

Some reactions might be called an "intolerance".  Everybody else can take this medicine, but it always makes me sick.  For example, the orthopedic surgeon gave me a sample of an anti-inflammatory medicine when my leg was injured.  It made my gut hurt a lot worse than my leg ever thought about hurting.

Another might be an excess sensitivity: a given dose of drug tranquilizes most patients, but puts one under deep anesthesia.  A more extreme example would be the time I administered a cough suppressant and the patient went to sleep for twelve hours.  The drug was just supposed to sedate the "coughing center", not the whole brain.  I was so happy when he woke up.

Toxic Epidermal Necrolysis is a very poorly understood condition.  Within days or weeks of drug administration, a patch (or patches) of skin dies, dries up, and falls off, leaving a raw area which can be rather difficult to heal.  It is especially frustrating, as one would like to give medication, but it is thought to be some type of reaction to medication.

These idiosyncratic responses to the drugs are by definition highly unusual, and therefore unpredictable.  They just don't happen very often, thank goodness, but this is small consolation when they do.  This is especially so on the rare occasions when there is an inexplicable fatal result.

Reactions to vaccines are uncommon, but because so many animals receive vaccines we have more experience with these.   A vaccine is a killed or weakened form of the germ that causes a disease.  We inject it into the animal to give him a pattern upon which to build his body defense response ahead of time, before he meets an actual, live, disease-causing germ.  We want his body to react to it in some degree.  Sometimes we get more reaction than we'd like.  The most common thing to note is some inflammation at the injection site: a pea-sized lump that develops a few days later, and goes away on its own.  On rare occasions, you get a larger reaction that requires treatment (four times in 29 years, for me).   

Since we are trying to stimulate the body's defenses, we sometimes get an allergic type of reaction.  Swelling of the lips and face may occur several hours after the vaccine is given, requiring treatment with an antihistamine or cortisone.  While this is crazy-looking and uncomfortable for the patient, it rarely escalates into anything dangerous (such as swelling that would close the airways and cause difficulty breathing).

Rarely, an anaphylactic reaction occurs.  You may be familiar with someone who is so allergic to bee-stings that they have to carry an "epi-pen" with them when outdoors.  In these cases, the reaction is very rapid, closing the airways, and can be fatal if not treated immediately.  Epinephrine (formerly known as adrenaline) opens the airways for emergency relief (most of the time).  Supportive care with antihistamines, cortisone, oxygen, and I.V. fluids may be needed as well.

I have only seen four of these in response to vaccination: three in my hospital, and one when a pet-owner administered vaccine which he had purchased over the counter.  When this happens, it is almost immediate. They begin have difficulty breathing, turn blue, and fall over.   I have been fortunate in seeing so few of these, and in having them respond rapidly to treatment.  Last week I had the very sad experience of losing a patient under these circumstances.  Unlike my other successes, this dog was quite old, and had pre-existing heart and airway problems.  He responded initially, but after three hours of struggling, his owners elected to throw in the towel (and I cannot blame them).

Sometimes the weirdness happens with no medicines at all.  This is Peanut.  Last week he came in for a check-up.  He wouldn't allow a nail-trim without a muzzle.  He also would not allow the muzzle to be placed on him.  After numerous attempts, during which he became more and more excited and angry, we finally slipped it on him.  As soon as it was buckled, he collapsed.  No breathing, no heartbeat.  Complete cardiac arrest, respiratory arrest.  Dead, basically.  Aggressive CPR (you don't want the details) resuscitated him.  Within ten minutes he was looking around.  Within 45 minutes, he was having this picture made, and went home.  Four days later, he still seems fine.  Chest X-rays and bloodwork are normal.   At present, his owners are putting off the ECG I want.

What happened?  We don't know.  I talked with Dr. John Sessions, a board-certified internist, while we were observing Peanut's recovery.  He speculated that Peanut just "used up" all that portion of his nervous system that works with excitement (sympathetic autonomic) , leaving the part that slows you down (parasympathetic autonomic) with no balance.  Thus, he not only got slowed down, he got stopped. If that explanation sounds a little contrived to you, I'm not surprised.  I just don't have a better one.

Incidentally, we trimmed his toe-nails while he was still comatose.  I need to find a simpler way of doing it next time.

Parvovirus shouldn't happen!

It's 6:30 PM and I'm waiting for someone from Monette, Arkansas (who didn't even call until after 5:30, and yes, we close at 5:00 today, thank you).  They think their puppy may have Parvovirus.  I think so, too.  It was "just fine yesterday", meaning a sudden onset of illness.  It's a puppy less than one year old.  It has vomiting and watery diarrhea.  Also, it hasn't been vaccinated!  That will be the fourth puppy in 24 hours with that history, and I'm sick of it.

Of course, I'm preaching to the choir, here.  If you're reading this blog, you are a pet-owner who cares enough to get informed about the health-care needs of your animals and get them taken care of.  It's not like these people don't care about their puppies, they are just in the "too little, too late" mode.

The problem is that we don't have any kind of great treatment for Parvovirus.  Once the live virus enters the body, in about seven days the puppy is going to get sick.  If he's a tiny puppy, it may attack his heart muscle and kill him outright.  Most will begin to vomit or have diarrhea, progressing to both.  The diarrhea becomes watery, and usually bloody.  The virus also attacks the bone marrow, where the white blood cells are made.  Now the body's first line of defense is gone, as well.  That means that other germs can just walk right in.  Countless virus particles are spewed out in the diarrhea, and they will live in the environment for months, providing a source of infection for other puppies.  Disinfection with chlorine bleach is necessary to kill the virus on floors, sidewalks, kennels, bowls, etc. [5 ounces of bleach diluted in one gallon of water is used to disinfect.]

Treatment of the puppy is limited to treating symptoms and keeping the patient hydrated with fluid therapy,either I.V. or subcutaneously (you hook things up like an I.V., but the fluid is dripped under the skin in about twenty minutes, where it is slowly absorbed over the next six to eight hours.  Maybe not as ideal as I.V. fluids, but works well in less severe cases, and costs about a fourth as much, and you can go home for nursing care instead of staying in the hospital.)  You give anti-vomiting drugs and sometimes they work pretty well and sometimes not so well.  Antibiotics are given to help combat the secondary invaders, though they do nothing to kill the parvovirus.  It's basically a supportive care situation.

In the early days (1980's) we gave a lot of anti-diarrheals.  They didn't work so well, and it was a bad idea.  The body is trying to get rid of a lot of nasty stuff in that diarrhea, and corking it up would be bad.  In the last couple of years, we tried the anti-viral drug in Tamiflu.  It looked promising, but didn't pan out. 

The devil of it is that I should never be having to treat these.  The vaccine works so very well to prevent the disease.  I have not seen a properly vaccinated puppy get sick in years.  You just start the vaccine at weaning, repeat a couple of times at four-week intervals (or 3-week, if you're a little paranoid, and you can add an additional booster dose at 18 weeks if you want to be doubly sure they have lasting protection).  Three puppy-care visits, preventing LOTS of diseases, getting started on heartworm preventive and flea control -- total cost is less than the first day's attempted treatment of Parvovirus. 

If I had a more successful treatment, this wouldn't bug me so much.  Fifty percent of these puppies will die, no matter what I do.  This is so preventable, so unnecessary, and so frustrating.

Pyometra

I got the call at 7:00 AM Saturday.  "I've been up all night with Fluffy.  She's been vomiting and had a lot of fluid from the other end."  With vomiting, I assumed she meant the dog had diarrhea.   Fluffy arrived wearing a diaper.  "How many times did she have diarrhea?"  "I don't think it's coming from there."  The lady couldn't bring herself to just say "vaginal discharge".  That's what Fluffy had, though, and lots of it, and it was nasty.  "She sleeps with us and I had to change the sheets."  I can believe that.

Fluffy is almost eleven years old and was never spayed (ovariohysterectomy: the removal of both ovaries and the entire uterus).  Fluffy's mom kept thinking that maybe sometime she'd like to raise a litter of puppies.  She never got around to that, but then she was afraid to have Fluffy anesthetized (she still needs her teeth cleaned).  Unfortunately, elderly intact female dogs develop female trouble.  After all those heat cycles and no babies, the uterus finally began to nourish a nasty infection instead of the litter of pups it was designed for. Pus instead of pups. 

Pyometra is pus in the uterus.  Fortunately, Fluffy began discharging it, which made the diagnosis easy.  Often the dog just has some non-specific "don't feel good".  Classical signs (in addition to vaginal discharge) include vomiting, excessive water drinking and urination, abdominal swelling, and a high white blood cell count.  Ultrasound imaging is a big help with diagnosing the ones that aren't discharging.

The dog's uterus is a Y-shaped, tubular organ -- two long tubes where the puppies would develop end-to-end like a string of sausages.  It's interior (which we scientists call "the lumen") has an intimate connection with mama's bloodstream.  It is across this same surface that the puppies derive their nutrition and get rid of their wastes.  This means that whatever is in the middle of the uterus has the potential to cross over into the bloodstream and be spread throughout the dog's body.  Not good.

Because it is a tubular organ, medical therapy is often ineffective.  You can give antibiotics to kill the germs, and the medicine travels through the bloodstream and permeates the wall of the uterus, but not much will get into the lumen.  You might be able to irrigate the uterus and remove a lot of the pus, but how can you be sure that you get into both tubes, and all the way to the end of the tubes?  The answer is that you cannot do it, much less be sure you did it.  Some dogs can be successfully treated by using a hormone-like compound called prostaglandin.  This stuff causes the uterus to contract forcefully, expelling the pus.  Treatment for several days with prostaglandin does cure the condition in some dogs.  For many, it does not. The treatment is unpleasant (though not dangerous) and the dog's condition must be monitored for several weeks to be sure that the problem is in fact resolved.

For these reasons, the treatment of choice is always the complete removal of the uterus.  If you are not raising puppies, it would be a lot easier for all concerned to have your dog spayed when she is young and healthy and you can plan for it, than to wait until she is old and sick and has to have emergency surgery with IV fluids, IV antibiotics, and intensive care.

I explained all this to Fluffy's mom, using color glossy pictures with circles and arrows and a paragraph on the back of each one, explaining what each one was.  Mommy doesn't want a hysterectomy for Fluffy, and she's afraid for Fluffy to be anesthetized.   Never mind that she's going to die unless we do the surgery today.

After the surgery was all over and Fluffy was recovering well, I apologized to the owner for "getting in her face".  You see, when she protested the surgery, I went into  "Dr.House" mode -- not nasty like House, but lots of graphic illustrations.  "If you don't do the surgery, Fluffy will die.  The infection wil spread through her bloodstream, shutting down her kidneys, damaging her heart, liver, going everywhere in her body.  Once, about twenty-five years ago, I let someone talk me into medical treatment of a dog, but they didn't come back for follow-up.  The treatment didn't work, and when they did come back, she had pus in her eyeballs!  She didn't make it.  You don't want the pus on your sheets, but it's okay to have it in her blood? We have to do the surgery today." [A true story, unfortunately]

All's well that ends well, but if you don't want to raise puppies, get the puppy-works taken out while the taking is good.

Treating Congestive Heart Failure

We talked yesterday about big, flabby, weak, stretched out of shape hearts.  These hearts can't pump blood very efficiently.  The body demands that a certain amount of blood get pumped around every minute on a regular basis -- that's Cardiac Output.  If the heart can't pump strongly enough to get that done with a normal number of beats per minute, the body may compensate by just having more beats per minute.  That only works up to a point, though.  It's possible for the heart to beat so fast that it doesn't have time to fill with blood between heart-beats.  Then you have a pulse deficit, meaning that when you feel the pulse inside the thigh, there aren't as many pulses as there are heart-beats.  This is bad.  When you can still compensate for the heart's weakness by increasing heart rate, and tightening down blood vessels to keep pressure up to vital organs, you feel okay. When this isn't enough to maintain cardiac output, you are de-compensated.  Now you don't feel good and you can't tolerate exercise.  Eventually you don't even have enough capacity to just sit there and breathe, much less eat, sleep comfortably, or exercise.

While there are many different medications available, there just a few basic approaches to helping a patient with a weak, flabby heart.  The analogy I like to use is that of an old horse pulling a loaded wagon up a hill.  When he is having trouble getting the wagon up and over, what can you do?

Step one: find a hill that's not so steep, or go around.  For our heart patient, that means don't overdo the exercise.  This is not like someone who has had a heart attack and is exercising to build up the remaining muscle.  With congestive heart failure, overdoing the exercise can put you in a crisis situation.  Another thing that makes the hill steep is being overweight.  Pounds of fat are miles of capillaries (microscopic blood vessels) and more work to do.  Lose the excess weight.

Step two: unload the wagon a little.  Here we're talking about reducing the circulating volume of fluid.  The reason that you restrict salt intake is that sodium is a very active little molecule in retaining water in the body.  Excess sodium in the diet means excess water retained, which is more load in the wagon.  Diuretic drugs allow the kidneys to let more water escape the body in the urine, again dropping the circulating fluid volume.  If you've accumulated fluid in the lungs or abdomen, it helps pull some of that out, too.  Furosemide (a.k.a. Lasix, a.k.a. Salix) is one of the most commonly used diuretic drugs for patients with congestive heart failure.

Step three: quit putting the brakes on the wagon wheel.  When a weak heart allows blood pressure to fall, the body puts an inappropriate defense mechanism into play.  In the wild, animals just don't live long enough to get this disease.  In the wild, if you've got low blood pressure, you're either bleeding or in shock, with blood vessels dilated and not functioning properly.  The body's response to this situation is to tighten those blood vessels to stop the leak.  This is a great idea if you're bleeding.  On the other hand, if your blood pressure is low because your heart is weak, tightening those blood vessels just makes it harder for the weak heart to get its job done.  It's a lot harder to pump fluid through a soda straw than through an open pipe.  Enalapril (a.k.a. Vasotec, a.k.a. Enacard) is a popular drug used to block this inappropriate body defense response.

Step four: whip the horse. Make that weak, flabby heart work harder.  Digoxin (derived from the older digitalis) has been a standby for many years.  This drug makes the weak muscle contract more forcefully, giving more output per beat, and a slower heart-rate.  Unfortunately, it has a narrow margin of safety.  The right dose makes your heart work more efficiently, but just a little too much makes it worse.  It must be dosed carefully, and tends to be used when the other approaches are not working.

There are certainly other ramifications to this disease, and many other drugs beside those mentioned.  There are also other types of heart disease to which this discussion does not apply. 

I'm no cardiologist.  When I have a patient with severe heart disease, we do our homework.  In addition to listening to his chest, we take X-rays to evaluate heart size and shape, and the condition of the lungs.  An echocardiogram (using the ultrasound) lets us see the heart pumping and valves functioning in real time, and lets us measure how well it is contracting.  Blood tests evaluate the extent of damage to other organ systems.  We also use the Idexx Telemedicine service (formerly Cardiopet).   The clips go on your pet, the telephone goes on the box, and the ECG (electrocardiogram) prints out in New Jersey.  There a specialist inteprets the ECG and the other data we have collected and consults with us on the best way to manage the patient.  Many pets with heart disease can have added years of a good quality of life.