Cardiovascular Disorders in Dogs

Spironolactone and Enacard for Treating Arrhythmias

Q: Dr. Mike: I am a new subscriber and think your site is excellent! I will try to make this as short as possible. Muddy is a 15(?) year old spaniel mix. He looks most like a King Charles - only black. I got him for 14 yrs ago from a shelter. He weighs 23 lbs (I can feel his ribs) and until recently appeared perfectly healthy except for a heart murmur. Although certainly not as spry as when he was a kid - he can still do stairs and a brisk, 2+ mile walk without a problem. No breathing problems and he never coughs. In checking him prior to surgery for a Sebaceous Epithelioma, my vet sensed an occasional arrhythmia. X-rays were followed by an echocardiogram. Basic diagnosis below... 1. Mitral Valve insufficiency w/ flail carnial mitral valve leaflet. 2. Concurrent tricuspid insufficiency. 3. Right and left atrial enlargement. (Mostly left, right is mild) 4. Occasional arrhythmia. Suspect atrial premature contractions. He is taking Enacard (.5 mg/kg) and 1/2 tab of a 25 mg/ 500 myl Spironolactone once a day for about 3 wks now. He is not taking any Lasix at this time. Considering that he had no prior symptoms, I am very concerned about the side effects of this combo of medications. My research shows the potential for dangerously high potassium levels, as well as a detrimental impact on his kidneys in general. I think the vet thinks I'm over-reacting. (See www.petrx.com/insert/enacard.html) I would like to hear your opinion on his treatment, as well as what kind of follow up is needed and how often -- if money is no object. What is the real potential for problems? I would also like to know if you think that a special diet and/or supplements are in order. Thanks so much for your help. Karen A: Karen- The potassium sparing effects of spironolactone, alone and in combination with enalapril (Enacard Rx) are supposed to be much less of a problem for dogs than they are for people. This is the consensus of several veterinary cardiologists based on the information in the texts that I have. So this is probably why your vet is not especially concerned about using this combination in treating Muddy. Despite this, there is a recommendation in Dr. Fox's text (cited below) to monitor potassium levels when using spironolactone in combination with enalapril and related medications. It is relatively easy to draw blood at regular intervals until it is evident that there is or is not going to be a problem. Among the veterinary cardiologists whose opinions I am familiar with there is not as much enthusiasm about spironolactone as there is among human cardiologists, though. They still really prefer furosemide when a diuretic is necessary, feeling that it is more effective. The current thinking on spironolactone in people seems to be that its major benefit is inhibiting aldosterone and that low dosages are just as effective, with 0.25 to 1mg/kg/day having this effect. If the intended use of the spironolactone is to lower sodium levels by inhibiting aldosterone then the potassium sparing effect may not be as great as it is when spironolactone is used to produce diuresis, since the dose for this use is 1 to 2mg/kg every 12 hours. It is supposed to be acceptable to use both furosemide and spironolactone when using spironolactone in the lower dosage range (0.25mg to 1mg/kg/day). Arrhythmias are worrisome and it would probably be best to consider having an examination by a board certified veterinary cardiologist if that is possible to arrange and you haven't done that in the visit to have the cardiac ultrasound examination done. Atrial premature complexes are not dangerous by themselves, according to Dr. Fox's book "Textbook of Canine and Feline Cardiology" but they can be a sign that a more serious problem is present, such as heart muscle weakness or cancer affecting the heart. A cardiac specialist can give you the best idea of the prognosis for the degree of valve failure present and the best intervals for monitoring the progress of this problem. Mike Richards, DVM 12/4/2001

Chronic Heart Failure - Could Enacard be Contributing to Arrhythmia?

Q: Dear Dr. Mike, Our 12 yr. old, 18 lb. mixed breed dog has been under treatment for CHF due to mitral valve failure. He has been taking Enacard (5mg/day) for the first seven weeks and is now also getting Lasix every other day. He is being fed a low-sodium diet. During his most recent examination, a heart arrhythmia was noticed. No lab tests have been performed on him since starting on Enacard. His respiratory rate is often around 40-45, with shallow breaths. His appetite is still good and no obvious changes in his urination have been noticed. He no longer likes to be picked-up from under his shoulders, which used to not be a problem. We can lift him supporting all four legs, which doesn't seem to cause him any discomfort. My questions are: 1) Could the Enacard be contributing to the arrhythmia? 2) How will we know if his kidneys are being affected since no lab tests have been performed since the Enacard? 3) Is the high respiratory rate due to his heart condition, the medication, or a combination of the two? 4) Is his chest sore from his condition, since he doesn't want to be picked-up in a certain way? 5) What are safe supplementation dosages of coenzyme Q10 and l-carnitine? Thank you very much for your help and for providing this valuable service for pet owners. Sincerely, Mark A: Mark- 1) I did not find any reports of arrhythmia as a side effect of enalapril (Enacard Rx) on the package insert or in the two pharmacology texts I checked. However, there is mention of a problem with hyperkalemia (too high potassium levels) in some patients who are being treated with enalapril and furosemide (Lasix Rx) and this could conceivably lead to arrhythmias. I suspect that isn't a common problem but it may be something to think about and it is pretty easy to check the potassium levels to make sure they aren't a problem. In addition, in dogs with pre-existing arrhythmia who are on anti-arrhythmia medications there is an increase in cases of sudden death in dogs taking enalapril, even though the survival times overall tend to be longer for these patients. 2) If he stopped eating or you noticed a marked increase in drinking and urinating (which may be hard to detect since furosemide causes this) then you should worry about kidney damage. It is much better to check for kidney damage through a urinalysis and blood chemistry testing after using enalapril, though. The best approach is to check the kidney related blood chemistry values and to a urinalysis weekly for the first month of therapy and then every 3 to 6 months, but few vets do this since many clients would refuse the medication if strict adherence to these testing schedules was insisted on. However, for owners who wish to be cautious, this is the recommended approach. We test after 5 to 7 days of use, when possible, and then try to get a test in one month and then at longer intervals (exact timing depends on the patient and the client). 3) I would suspect that the high respiratory rate is due to his heart problems, although I wouldn't want to rule out an undetected respiratory problem since things like laryngeal paralysis are common in Labradors. I can't recall seeing this kind of increase from the medications being used in our patients. 4) Lots of dogs with heart disease don't want to be picked up by any method that might compress their chest. I don't think this is from pain, I think that they get uncomfortable quickly when there is any compromise in their ability to move air or blood and so they get wary of these types of situations. I could be wrong, that is just my impression. 5) Dogs are usually given 220mg/kg of body weigh of l-carnitine every 12 hours up to a dosage of about 2 grams per 12 hours. There are a number of dosages for CoEnzyme Q10 that I have seen but the range is usually between 30 and 90mg every 12 hours. Mike Richards, DVM 8/24/2001

Failure of The Mitral Valve and Diet

Q: Dear Dr. Mike, I am sorry to hear of your health problems recently. I surely hope that they do not turn out to be something serious or untreatable. I have a little chihuahua/terrrier spayed ten-year-old female dog who began to cough several months ago. After a while when the cough would not go away, I brought her to the vet. An ultrasound has determined that she has Left Atrium enlargement, and the valve that goes into the fourth chamber has scar tissue on it, causing leakage (back flow) of blood and a loud heart murmur. In addition, a small quantity of fluid was found in the lungs and her liver is enlarged. Blood work came out well: kidney function is fine, and there is no sign of Cushings disease. She is on Lasix and Elanfronil (sp?), the first to reduce fluid buildup and lower blood pressure, the latter I think to alter the kidneys' signal for more fluid. Also, she is on Pepcid AC to reduce acid because some gastrointestinal bleeding was found I think. Sometimes she collapses suddenly, and the vet has said that's due to the leaky valve and not enough oxygen-rich blood going to the brain. What I want to know is this:

1. How much and what type of exercise can you recommend?

2. What type of diet? She is finicky. We are trying to get her down from 14 lbs to about 10. I changed her diet two weeks ago and she's already lost 9 oz.

3. How serious does this sound to you? Is her life in danger? Can she have a heart attack? Can a chamber burst?

4. Should I have any concern about the medications? This is a very special little dog, highly intelligent, highly charming and humorous. I'd like to keep her around as long as possible, of course! Any help and insight would be greatly appreciated, Wendy A: Wendy- I am doing well now. I appreciate your concern, though. I feel fortunate that nothing serious was found. From your note, it sounds as if your dog has failure of the mitral valve, which is the valve located between the left atrium and the left ventricle. This is the most common valve failure in older dogs. Failure of this valve usually eventually leads to chronic heart failure, as the heart becomes less efficient and is unable to pump adequate amounts of oxygen rich blood out to the body. The brain is the most oxygen sensitive organ in the body and some dogs with mitral valve failure will have episodes of syncope, or fainting, due to periods of inadequate oxygen flow to the brain. This is most common after a bout of severe coughing occurs. It is a serious sign because it indicates that there really is a serious lack of oxygen to the brain at times. It is often possible to help the heart a great deal when mitral valve insufficiency is present. The ways this can be done are to lower the blood pressure, making it easier for the heart to pump blood into the circulation, lower the volume of blood the heart has to handle, and increase the strength of the heart muscle. It is also possible to replace the valve in larger dogs but this isn't done very often. Lowering the amount of sodium in the diet to reduce water retention (and blood volume) is helpful. Diuretics such as furosemide (Lasix Rx) also help to reduce the blood volume, as well as having some effect on blood pressure. Furosemide has a minor anti-inflammatory effect, which can also help a little in controlling the coughing. Enalapril (Enacard Rx, Vasotec Rx) and other angiotensin-converting enzyme (ACE) inhibitors have several beneficial effects. Angiotensin II is released by the kidneys (and other organs) and causes the blood vessels to constrict, which raises blood pressure. Kidneys like high blood pressure because they get more blood flow. Unfortunately, this isn't good for a failing heart. So ACE inhibitors lower blood pressure by stopping the vasoconstriction, causing dilation of the arterioles and veins (think of two sizes of hose --- the smaller one requires more pressure to get the same amount of water through it). They have some diuretic effect, lowering the amount of blood volume the heart must circulate and they also interfere with local control of vascular growth and remodeling that is also controlled by angiotensin-converting enzyme and this is a beneficial effect. There are some down sides to the use of enalapril. In some cases this medication can cause severe lowering of blood pressure and this can lead to fainting when it is used. This is actually not usually a serious problem but it is frightening and it can lead to the more serious problem associated with enalapril, which is kidney failure in a few patients. Kidney failure associated with enalapril is not a common event (we have never seen this side effect in our practice) but it does occur. It is most common in the early stages of use of enalapril, which coincides with heavy use of diuretics as vets try to quickly reduce the work load on a failing heart. It is a good idea to monitor lab values for kidney function one to two weeks after starting enalapril and then again after a month and perhaps three months. Exercise is a tough issue in patients with mitral valve failure. There is no question that reduction in exercise is beneficial when there are obvious signs of heart failure, such as you are seeing now. However, as the medications work and the heart condition stabilizes there are no really clear guidelines for how to handle exercise. Please remember at this point that I am an avid runner and rower and prone to believing in the benefits of exercise. Having said that, my personal opinion is that carefully controlled exercise that does not exceed the heart's compromised ability to respond to it is beneficial. It may be necessary to start an exercise program very slowly and work up to moderate exercise periods daily over a very long time. Not all vets feel this way. Many prefer to try to limit exercise long term as part of the therapy for mitral valve problems. You will need the cooperation of your vet to monitor the effects of exercise. If your vet disagrees over the benefits of exercise it will present some problems and it may be best to honor their approach to this problem. The only big dietary objective in heart disease is lowering the salt content. This is a little hard to do because just like people, dogs like salt in their food. There are commercial reduced salt diets, such as Hill's h/d diet. Some dogs will eat these foods readily while others are very reluctant. It is worth trying one of the commercial heart diets. If that doesn't work, just remember that the objective is to lower sodium in the diet and pay attention to the sodium content of foods, choosing foods and treats that are lower in sodium. This is especially true for dog treats, which are often very high in sodium. Coughing is part of the problem. Controlling the cough can be beneficial. We use hydrocodone as a cough suppressant and it seems to help a lot, especially in little dogs that faint after coughing spells. It may also be beneficial to add spironolactone ( another diuretic but one that inhibits aldosterone, which is a hormone that tends to cause conservation of sodium). Some dogs also seem to benefit from the use of digoxin, which strengthens the heart muscles a little. Vets are always arguing over whether digoxin really helps, or not, and I am not sure that there is a clear answer after twenty years of reading both sides of the arguments. It is usually possible to help dogs with mitral valve failure adjust to the problem and most will live a long time with the aid of medications and good overall care. The ventricle enlarges but this does not pose a threat of rupture. Heart attack, as it occurs in humans, is a very rare event in dogs. However, there will eventually be heart failure that will no longer respond to medications and nursing care. It may be years before that happens, though. The odds are on your side for success in treating the problems that are present now and for good control, for some time, of the ongoing chronic heart failure. Pay close attention to how your dog acts and feels and keep working with your vet to control changes as they occur. Mike Richards, DVM 12/4/2000

Medication for Heart Failure

Q: Dr., I am a happy subscriber. Matter of fact your web site has helped me tremendously. One day about 2 years ago my dog 13 at that time just started shaking and within hours could not stand up. I was certain he had a heart attack or stroke, I did not want to take him the Dr. afraid they would want to put him to sleep. Instead my daughter got on the Internet, found your site. We found out about vestibular syndrome. It gave me hope to get through the night and just as you said within 24 hours he was able to get up and after a week was just fine. He did have a repeat about 4 months later but was not as severe. My Crocker, Rusty, is now 15 yrs. old, and still goes to work with me every day. However, he now has new problems. Several months ago I took him to his Dr. He was panting all the time, drinking lots of water and coughing. After blood work, x-rays, etc., they said he has an enlarged heart and a collapsing trachea (more in the chest than the neck). He weighs 32 lbs. they put him on 5 mg. Enacard and 12.5 mg. lasix. The medication helped immediately. He did well for a month or so then worsened again, the Dr. had me increase his medication, same dose but now I am giving it to him morning and evening, (daily 10 mg. Encard 25 mg. Lasix). I went in the other day to get his prescription renewed. They were out of the lasix for dogs so they gave me lasix for humans it only comes in a 20 mg. pill so the Dr. had me increase the lasix to 3/4 pill morning and night total of 30 mg. daily. For two days now he seems worse, he is panting a lot, not much coughing. I wonder if human lasix is not as effective on dogs or is he just getting worse. The Dr. said that in time he will get worse. She said we cannot increase the Enacard any more, we will have to go to other drugs may even have to go to nitro-gyserin. By the way, they did at first suspect cushings disease, but his tests were negative. The Dr. also cleaned his teeth which were in bad shape, she said the bad teeth may have somewhat contributed to his heart condition (they pulled one tooth). He had not had his teeth cleaned for three years. They are putting him on antibiotics for a week once a month. Please tell me your thoughts on Lasix and perhaps any other medications or ideas you may have. Thank you, Jo Ann Answer: Jo Ann- I think that furosemide (Lasix Rx) is a very useful medication for pulmonary congestion from heart failure. The combination of furosemide and enalapril (Enacard Rx) is a good choice. Recently, there is information suggesting that adding spironolactone, another diuretic, can also be very helpful. This has not been proven to occur in dogs but it works well in people and early reports in dogs are encouraging. The dosage is 0.25 to 1mg/kg per day, which is actually below the effective diuretic dosage but high enough to help with heart disease by inhibiting aldosterone, which can increase the blood pressure. This is an option to consider. Other medications may be necessary to address specific problems that occur as heart failure progresses but it sounds like your vet is preparing for these possibilities. There is evidence to suggest that pulse therapy with antibiotics to control tartar and gum disease can be helpful and this is currently becoming a popular approach to this problem. Mike Richards, DVM 10/6/2000

Drug Interactions between Heart Medication and Dental Surgery

Q: Dear Dr. Mike, My 15-year-old poodle has an enlarged heart and is on Seleglian (5mg hcl) and Inecard (1 mg). He needs dental surgery and my vet wants me to give him Clavamox (62.5 mg) before his visit. When I asked my vet if it was okay to give him the Clavamox while he's on his heart medication he said "It should be alright." Can you give me a more definite answer about any possible side effects or drug interactions. Thank you for providing such a valuable service to all pet owners! Sincerely, Nichole A: Nichole- I think that your vet is worried about potential reactions between selegiline and the amoxicillin/clavulanate combination (Clavamox Rx) and is reluctant to give you a definite answer due to this. The problem isn't that there is any known interaction. It is just that selegiline is a very new medication and it does interact with some medications (most notably meperidine (Demerol Rx) and amitraz (Mitaban Rx) and other MAO inhibitors. There may also be reactions with tricyclic antidepressants such as amitriptyline. I really think that there isn't going to be a problem but it takes a while to find out all the possible reactions to new medications so you should watch for any signs of problems and report them immediately to your vet, just in case. Mike Richards, DVM 3/24/2000

Using Enacard Early for Cardiac Insufficiency

Q: Dear Dr. Richards, I understand that some cardiologists are recommending the use of Enocard early in cardiac insufficiency rather than waiting til later, the reason being that it seems to slow the process of deterioration. Makes sense, but how do you know you're using the right dose, assuming you're treating a pet that is basically still asymptomatic? It's been suggested I consider starting my 12 yr old, heartworm positive Peke (yep, same one I asked your opinion on re: the adulticide tx) who has an enlarged heart, and also a 9 yr old "sleeve" (read "itty-bitty") Peke who has about a grade II/VI murmur and turns blue when excited....I guess I could excite her and see if she still turns blue?? BTW I chickened out on the adulticide and am treating the HW+ girl with ivermectin. So far, so good. She coughs less (?) and remains spry. She also gets a scant 1/2 baby aspirin QD. Thanks again for your time. I really enjoy visiting your site. Sue A: Sue- Your question hits right at the center of a strong debate in veterinary medicine right now. When to start angiotensin converting enzyme inhibitors (ACE inhibitors) like enalapril (Enacard RX) is a difficult question. There is no clear evidence that starting enalapril early slows the progression of heart disease associated with the most common heart murmur in older dogs, mitral valve insufficiency, a form of left sided heart failure. This is probably the problem in your 9 year old Peke, based on the odds, but it would be a good idea to confirm this with your vet. On the other hand, there is no clear evidence that enalapril won't help in these conditions, either. Logically, a case can be made for either scenario. Enalapril does help in most patients with mitral valve insufficiency once obvious signs of heart failure exist, such as pulmonary edema and coughing. Heart failure induced by heartworms presents a different problem, in that there aren't any studies that I can find on the benefits of enalapril in right sided heart failure associated with heartworms. There may be some benefit once obvious heart failure signs are present, such as coughing, though. This is a situation in which progression of the disease is controlled by factors external to the heart (the heartworm damage in the pulmonary arteries) so the medication will not slow the progression of the disease much, probably. A large number of small dogs with chronic heart murmurs never develop heart failure. These patients would not benefit from enalapril administered early, since they are going to be OK, anyway. Whether enalapril helps the remaining dogs who are going to have heart failure at some point is unclear. So I tend to just wait and see which ones have problems and then treat those patients. I am not sure that is the best approach but it is the one I am comfortable with. If your vet has a different opinion I can't say it is wrong. Unfortunately, this is one of those situations in which you just have to do what your gut instinct tells you is best and hope you're right. The good thing is that either approach is probably OK. The dosage is pretty standard for enalapril, so there aren't major dosing worries. Diuretic dosing is often adjusted to match the patient's need but the ACE inhibitors are usually used at standard dosages. I know this didn't give you a clear answer but I hope that it helps some in your decision making. Mike Richards, DVM 2/23/2000

Heart Blockage - Pacemaker Implant

Q: We have a female, shepherd-mix dog of approx. 12 years of age. She has been diagnosed with second degree heart block. Our vet remarked that he had seen a gradual dropping in her heart rate over the past several years, but when I took her in for her immunizations this year, the rate was 46 bpm. After an evaluation by a vet-cardiologist who lives not far from our town, we were told that it was second degree heart block. The rate improves with administration of atropine. A thyroid function test showed her to be slighly low, but administration of thyroxin hasn't improved the heart rate at all. She was also placed on theophylline, an initial dose of Theo-Dur at 200 mg BID made her sick. So, the amt. was reduced to 100 mg BID. It had no effect on the heart rate--in fact for the few days that she was on the 200 mg./BID regimen, it did not seem to boost the heart rate either. We're concerned for her. She's a very special dog and we're anxious to have her with us as long as is possible. Since this drop in heart rate has been ongoing, will it continue or has it plateaued out? If it does continue, is our only recourse to consider a heart pacemaker implant? Are there centers for this type of surgery not too far from us? We live in northern New Mexico. Any and all information you might be able to provide would be greatly appreciated. Thanks! A: S- It is important that you understand that I am not a cardiologist or a specialist of any kind. I just research questions and provide the best answer I can based on that -- although sometimes I have enough personal experience to add my own thoughts to the commentary. This isn't one of those times, though. Unless there are new medications that I am not aware of, the current recommendation for second degree heart block in which the heart rate slows to below normal rates (which 46 beats per minute usually qualifies as) and in which a primary disease is not identifiable, is to implant a pacemaker. Problems which can lead to second degree atrioventricular blocks are bacterial infections, cancer, toxins (usually heart medications being used to treat other conditions), systemic illnesses that disturb electrolyte balances and scarring in the area of the AV node. There are some breeds prone to AV blockages (Dr. Morgan's textbook "Handbook of Small Animal Practice" lists dobermans, cockers and pugs). I suspect it is rare, based on this list, to find a treatable underlying cause that isn't pretty obvious on initial exam. Hypothyroidism may or may not contribute to AV nodal disorders based conflicting information in the literature. I suspect it is a pretty rare cause of this problem, at most. I wish I did know where the best specialists in different areas of the country were --- I hope to someday be able to compile such a list --- but right now I can't make a recommendation in your area. Hopefully your vet can do better. Mike Richards, DVM 9/4/99

Heart Problems or Seizures?

Q: Hello Dr. Richards, First, I wanted to tell you that your site has been most helpful to me. I found a lot of information that has helped me through this tough time. I have a 15 year old miniature schnauzer, TK, which has been pretty healthy, except for some arthritis (he's taken Rimadyl on and off). About a month ago I noticed that he started drinking a lot more water then usual so I took him to the Vet, which did a blood panel to see if there were possible kidney problems. The blood panel came back good, except for the thyroid and anemia. None at levels that the Vet felt we needed to do anything about it. He then suggested Anypril, which I gave to TK for about a week. That's when I started to noticed what I thought were seizures. He would cough, then fall to the ground and stay there for about 5 seconds, eyes open, then he gets up like nothing happened. I thought his legs were moving like convulsions, but it could have been because of the heavy breathing. The coughing always preceeds these fainting/seizures. In talking to my dad (which is a physician) he said that maybe he is having heart problems. I took TK to the Vet again, which did a chest x-ray and EKG. The Vet told me that he had fluid in his lungs and that part of his heart was enlarged. He put him on Lassix and Enacard. The 'fainting' episodes seem to have slowed down, but now TK has no appetite whasoever. I have tried every trick in the book to get him to eat, and my last resort is filet mignon! :-) The Vet has not ruled out seizures yet, because since I haven't seen one in a couple of days, that doesn't mean he is not having them. Anyways, my questions are the following:

1. Could Enacard or Lassix be causing TK's lack of appetite?

2. Based on my description, have you seen/heard of any symptons like TK's - coughing/fainting or seizure?

3. My big worry right now is his appetite. Any suggestions in this area or what could be causing it? He refuses everything, including the dog treats he's always loved.

4. How long can dogs go without eating? He seems to like something for the first time, then snubs it. Should I be worried, or will dogs eventually eat when hungry? Any other information you can give me would be greatly appreciated. Thanks! *Chris*

A: Chris- 1) Both enalapril (Enacard Rx) and furosemide (Lasix Rx) can cause gastrointestinal problems but usually these are problems like vomiting or diarrhea rather than loss of appetite. Some dogs are pretty resistant to actually vomiting but appear to have nausea based on their reaction to food so perhaps this is happening. Despite the fact that these effects are sometimes seen with these medications they do seem to be infrequent enough that it is important to consider other possible causes. 2) A lot of people have problems distinguishing fainting (syncope) from seizures. This seems to be especially true of syncope associated with heart conditions since some dogs really do seem to tremor or to struggle rather than totally losing consciousness and then recovering, when episodes of fainting occur. Seizures are common in older dogs, so it would not be unusual to see these, either. If you have a video camera it might be worth trying to videotape one or two of these episodes so your vet can see exactly what is happening. Dogs that are seizuring often urinate or defecate, which is unusual with fainting. Rhythmic movement or tremoring is more common with seizure activity, too. 3) Appetite stimulation in dogs is frustrating. They don't respond as consistently to medications that work really well in cats. Cyproheptadine (Periactin Rx) is the medication that seems to work the best. Most people use around 1mg/kg two to three times a day, I think. 4)Dogs can go a long time without eating. Dogs usually do not experience severe secondary problems when they choose not to eat, which is very different from cats. How long a particular dog can go without eating depends on the dog's condition prior to the time it stops eating but most dogs can easily manage a week or more of not eating. However, total lack of appetite is a sign that something major is happening in the dog's system and a concerted effort to discover what is wrong is in order. We have seen inappetance in a number of our patients with heart problems. Sometimes I think that the dogs with this problem are almost afraid to eat because they just don't have enough reserve to eat and continue to oxygenate their blood. If this is the case successful treatment of the heart problem will resolve the inappetance. It really does sound like the heart problems may be the major problem based on the response to treatment but it is important to continue to think about other possible problems and to monitor the response to treatment so that improvement continues. Your dad made a good observation and your vet seems to be willing to think about problems other than those that he or she was originally focusing on and that is an important quality to have --- especially when there is a chance of concurrent problems or a complicated problem. I hope that TK continues to improve on the heart medications and that this resolves the other symptoms you are seeing. If not, you'll just have to keep looking for other problems --- and remember that in older pets it is not unusual to have more than one problem at the same time, which can complicate the diagnostic process. Mike Richards, DVM 8/10/99

Heart Disease, Cushing's or Addison's?

Q: Dear Dr. Richards, Thank you for your quick and very helpful response to the problems with my parents Westie. Your message helped my parents to go back to their vet and ask them to do x-rays of her heart/chest and her kidneys today. According to the vet the x-rays showed no signs of kidney problems, but said that her heart was about 2/3 larger than it should be and that there are pockets of fluid around her heart. He prescribed FUROSEMIDE (or FUROSENIDE, it's hard to read) 1 tablet every 12 hours. Each is 12.5mg. She is to take this and go back on Thursday to see if it has drained the fluid. He said she would then have to be on another prescription to keep the fluid out. He took her off her thyroid medicine and the RIMADYL and MSM. He said to continue the antibiotic, CEPHALEXIN. He also said that if they do anymore testing for Addisons they would wait to see what happened with her heart first. My Mother questioned him again about why Addisons and not Cushings, but did not get any clear answers. The vet said he didn't feel she was having seizures, but that the episodes were caused from a lack of oxygen to her heart. At one time he mentioned when Bianca (the Westie) was on the table that she was turning blue even then. How does all of this sound to you? I also was concerned about just dropping the thyroid medicine. Is it something that you should gradually be taken off of? One of the things that really caught my interest in your reply was the information on cardiac disease. Do you think we are looking at a heart problem that is showing the symptoms we are seeing? Or does a disease like Cushings and Addisons cause the heart problems so we could be looking at two things, one causing the other? I did look up the information on Furosemide on your site and see that is seemed to be listed under Cushings. Also, I don't understand the vet telling them that her heart is 2/3 the size it should be. Does that mean swelling? Is that a normal thing with cardiac problems? He also mentioned to my parents that this fluid is not a good thing and that most dogs do not have a long life span with this problem. I apologize for asking so many questions, we are just so confused and want to do everything we can to help her. Thank you again for your help. It is so nice to have someone to talk with who understands all of this. Lisa A: Lisa- I think that it is very likely that there are two problems. Heart problems are not that unusual in older dogs and neither are the hormonal disorders such as Cushing's disease and hypothyroidism. Heart disease is usually more life threatening than the hormonal problems and it is reasonable to try to establish how much of the problem is due to the heart first and then looking for other problems if it still seems warranted later. There is no need for a withdrawal period for thyroxine. Dogs have a large reservoir of this hormone in their body and do not have a sudden drop in availability of the hormone, as sometimes occurs with other hormones such as cortisones. I tend to disagree about the prognosis for chronic heart failure. We do have some patients who don't respond well to medication and do not live for long periods after diagnosis but the majority of our patients live several years if their owners will help in managing the heart failure. I tend to favor enalapril (Enacard or Vasotec Rx) over the long term instead of diuretics like furosemide but it is often necessary to use both. Changes in diet can be helpful if a dog will eat a low sodium diet. It is sometimes necessary to add digoxin as well as enalapril and a diuretic. There are veterinary cardiologists who can help with managing difficult cases and if your parent's Westie doesn't respond well to treatment it would be worth asking for a referral to a cardiologist. Heart enlargement usually occurs because the heart muscles are weakening or one or more heart valves are not working fully. This makes it harder for the heart to move blood efficiently and some blood isn't pumped out of the heart chamber. The heart still needs to move as much blood as the body needs, though -- so the heart enlarges in an attempt to hold both the amount of blood it can not longer get out of the chamber the valve leaks into and the amount that it would have normally pumped into the circulation. This causes the heart to enlarge. In situations in which the heart muscle is failing the enlargement occurs because the muscles simply are not strong enough to hold the normal fluid volume and they just expand. Sometimes the heart appears to be enlarged when it actually isn't. This happens when there is a tumor attached to the base of the heart or when there is blood or fluid accumulation in the pericardium, the sac that contains the heart in the chest. These conditions are not nearly as likely as chronic heart failure but need to be considered if treatment doesn't seem to be successful. Ultrasound exam is helpful in distinguishing these problems from the valve or muscle weakness problems. I am pretty sure that your parent's vet is planning on switching to or adding enalapril or a similar medication based on your note. Hopefully there will be much less fluid accumulation on the next X-ray. Then it will be a matter of continuing to monitor the heart problems and not forgetting about the other problems if they don't resolve. I would be more concerned about Cushing's disease based on the history than I would about Addison's disease but there are sometimes things about the examination or lab results that make someone suspicious about a disease that just don't get relayed clearly or that are just strong hunches based on previous experiences. If your parents keep working with their vet those things will get sorted out over time. Mike Richards, DVM 4/16/99

Typical Time to Monitor Heart

Q: Dear Dr. Richards, Today my parents took their little Westie back to the vet to check the fluid around her heart. They did more x-rays and he said that there wasn't much change yet. He wants her to continue on the Furosemide but increased the dosage to 1 1/2 tablets every 12 hours. He also changed her antibiotic to BAYTRIL 60. It is a large tablet and he said to either give her one a day or break it in half and give her half twice a day. I'm not positive, but I think this was done because her urine infection still has not cleared. My parents are doing the half twice a day. He doesn't want to see her for 10 days. I would think her heart should be monitored sooner, but is this a normal time? I want to thank you for your response to my last message. When my Mother read what you said about the prognosis I saw her brighten up right away. You have really helped us all in understanding these problems and to know what to check into further. This little dog means so much to my parents and I know they want to do everything they can to help her. I'll be honest, I get nervous about how their vet is responding to the problems. Thanks again, Lisa A: Lisa- It is sometimes hard to evaluate how important it is to recheck a patient or to seek a second opinion when a patient isn't getting better, but isn't getting worse, either. I try to follow the philosophy that I should evaluate the whole patient, which means that I am often content if a pet is obviously feeling better even when lab work or clinical signs do not seem to be improving as rapidly as the patient's spirits. On the other hand, if a patient doesn't seem to feel better I tend to worry a lot, even if there is some improvement in lab values or clinical signs. If your parent's Westie doesn't seem to be improving then I think it may be worthwhile to seek a second opinion. I would try for a specialist just because they tend to have more experience at and often better equipment for interpreting how severe a problem is. It is always hard to figure out when it is really necessary to go to the expense and effort of finding a specialist. You just have to follow your instincts (or in this case, your parent's have to follow theirs). Mike Richards, DVM 4/17/99

Fluid Around Heart- Bailey

Q: We have a terrier/cocker/etc. mix dog and recently he has had cold-like syptoms. Up until 3 weeks ago he was very playful and had all kinds of energy. We took him to our Vet and he first prescribed antibotics and told me that he was concerned about the size of Bailey's stomach. He told us that if the breathing did not improve, or if his stomach got bigger to bring him back. Well it did get bigger, and the Vet did X-rays and blood work. He told us that fluid had surrounded Bailey's heart, and he was unable to see the heart in the X-ray. He said that he thought it was a heart defect and there was not anything that he could do. He also said that the fluid was only allowing Bailey's lungs to expand 60% of their capacity. Bailey is about 22 pounds and he prescribed Lasix three times a day. Is there anything else that we can do? We are just sick about this. The Vet said that we would have to put Bailey to sleep if the Lasix did not work, or stopped working. Please help us, I feel as though I am losing a child. We adopted Bailey from the Humane Society and he has been the best dog anyone could ever ask for. We love him dearly and want to do everything possible. Thank you so much for your time. Sincerely, Heather and Jeff A: Heather and Jeff- It is not possible from your email to really give you much idea of a prognosis or even diagnosis. It sounds like Bailey may have either pulmonary edema, pleural effusion or pericardial effusion. Of these conditions, pericardial effusion. If this is a pericardial effusion it is very important to get a second opinion as quickly as possible because it can cause death rapidly and it sometimes treatable surgically. The other conditions should have other possible treatment options as well. They can be very serious and potentially fatal and a quick second opinion would still be a good idea. If Bailey is not visibly improving on the medication please do not delay getting a second opinion. If it is easily arranged in your locality it might be a good idea to see an internal medicine specialist or veterinary cardiologist but I wouldn't do this if it would add any delay in getting another opinion. I wouldn't even hesitate to get a second opinion from the same vet in this case. Sometimes it doesn't occur to a vet that people really seriously want to pursue aggressive treatment until they ask for a referral or until they show up and say bluntly that they want to be aggressive in treating the problem and indicate both the willingness and ability to pay for aggressive care that might not result in a good outcome. Good luck with this. Mike Richards, DVM

Bailey update

Q: Dr. Richards, Thank you so much for responding to my email. We took Bailey to another vet yesterday. I took the results of the blood work and the x-rays for him to look at. He did a urine test and a parasite test as well. He found an infection in the urine and prescribed Cephalexin three times daily. The parasite test was negative. After looking at the x-rays, he agreed that fluid was not allowing the lungs to expand fully, however he said that the lungs looked healthy. As for the heart, he could not see it either. He said that he was going to treat Bailey for heart failure and prescribed more Lasix and Cardoxin (0.7 ml twice daily), which he said might cause vomiting so he gave me Metoclopramide ( twice daily). One thing that he did say that if the fluid did not drain with the medication, he could drain it. Of course I asked if the fluid would come back and he said he didn't know. At least he seemed to want to try other treatments and that made me feel better. I am supposed to call him Monday and let him know how Bailey is doing. I will sure ask him about the problems that you suggested. Bailey does seem better to me. Although his belly is pretty much the same size, his breathing seems better ( it is not as loud). He wants to play more and isn't as tired. I just hope that all of these medications are necessary and hope that he can be with us for a long time. Once again I appreciate your response and am very impressed by your timing! Thank you so much for your time and expertise!!! Sincerely, Heather, Jeff and our buddy Bailey

Effectiveness of Enalapril (Enacard Rx) and Link between Periodontal Disease and Valve Failure

Q: Hello Dr. Mike. My dog is a poodle. I do not know his age, as I found him approximately 6 years ago. When he was first examined, I was informed he had a heart murmur (grade IV/V) on the left side. He always tended to cough easily when excited. I was told he had a weak, collapsible trachea. In the past year, the coughing persisted. I took him to a cardiologist, who informed me my dog had valvular disease. My dog's left atrium is enlarged, and two of his valves are leaking. The vet informed me that Enacard could actually reverse his condition, however, I was informed by another vet that nothing short of a transplant could correct his condition. So my questions are: 1. Is this condition reversible with medication? Will Enacard shrink the size of the swollen atrium or just slow the pumping of blood down? 2. My dog's teeth have always been in horrible condition, even after cleanings. I read that tooth and gum disease could lead to valvular disease. Could the condition of his teeth prior to me finding him, caused his heart problems? Thank you for your time A: Einstein- I think that sometimes vets try to oversimplify things and confuse people. Of course, it is possible that I just disagree with your cardiologist and if that is the case it is also possible (maybe even likely) that he or she is right and I am wrong. But this is what I think: Enalapril (Enacard Rx) will probably improve the quality of life for your dog. It is a worthwhile medication to consider. I know of no evidence that it will reverse valve damage but it may be possible that the effects it has on blood pressure may relieve some of the atrial enlargement. I think that valve replacement might be less drastic than a heart transplant but isn't much more likely to be practical for most pets. I do not believe that periodontal disease has been proven to contribute to valve failure in the heart, either. I do think it is entirely possible that the same underlying cause of the gum disease causes similar effects in heart valves. The cause of the weakness in the connective tissue of the mouth may also affect the connective tissue in the heart valves. Of course, that is just another unproven theory, it is just the one I like. Keeping the teeth clean really seems to improve the quality of life for dogs with periodontal disease. I don't want to discourage you from cleaning teeth or from using Enacard. I think both are very helpful. Mike Richards, DVM

Syncope (fainting due to heart disease)

Q: Dear Dr. Mike, (or whoever) I was reading up on the net about seizures because my dog recently had two within a period of about 3 months and he's never had them before. When people explained their dog's seizures they weren't the same as mine. My dog didn't just move one foot or go unconscious. My dog is a mixed terrier mutt (the best kind), he actually looks like he has some snauzer and shepherd and wolf in him, and he's about ten years old. About a week ago he had his second seizure where he would get restless, fall to the ground paw the air with all feet and let out this horrible sounding wail that puts me into tears. When I described this to my vet over the phone he acted like it was no big deal and said it sounds like he had a seizure. Just keep an eye on him. I'm really scared. Is this something that can occur in dogs as they get older? Does this hurt my dog? Is that why he wails so loudly? Should my vet be running tests on him or should we wait and see if they become more frequent? A lot of changes have occurred in my dog over the past year. He doesn't run or bike with me anymore. We can mention the word walk around him without spelling it because he never wants to go out. He's gained about ten pounds although he eats the same. I cry sometimes because his age is showing. And yet if there is a squirrel or deer or bunny out he will be off in a second so I know he can still run. But these seizures really scare me. Oh yea. They usually only last maybe a minute and then he gets up, shakes himself off and goes back to bed. Any help will be greatly appreciated. A: I think that it is possible that your dog is having seizure episodes. The exact symptoms can vary from dog to dog quite a bit. The vocalizing worries me, though. While this can occur with seizures it seems to occur more often with syncope (fainting due to heart disease) in our practice. I really think you should insist on a good physical exam and possibly lab work to rule out heart disease and check for treatable reasons that a seizure might have occurred. Mike Richards, DVM

Heart Failure Life Prognosis

Q: We have a 12 year old doberman who has recently been diagnosed with left-sided heart failure. He has been started on Lassix and Enacard and placed on a low-sodium diet. His coughing has almost subsided and we will re-x-ray soon. What is the prognosis for an old dog in excellent physical condition and ideal weight? Can we expect to enjoy his companionship for another year or two? A: Eric- As long as your doberman does not have cardiomyopathy (weakness of the heart muscle) as the underlying cause of the heart failure, the prognosis for control of heart failure symptoms using medications is pretty good. While no one can give you any real idea of how long these medications will work for any individual dog, it would not be unusual at all for them to work well for one to two years or more. Mike Richards, DVM

Kennel Cough or Heartworm?

Q: Hi Dr. Mike, I have a 5 or 6 year old boxer. We got him in August from the pound. When we first got him he had a cough which the people at the pound said it was probably kennel cough. The cough went away at first but comes and goes quite often. He mostly coughs when he first gets up and when he goes outside and is running around. Is this just because of the weather or is this something we should get checked out. A: It would definitely be best to have your dog examined. I do not know if heartworms are a problem in your area, or if your dog has previously had a heartworm exam (including an occult heartworm exam) or not, but this would be the first suspicion I would have here in Virginia. Other heart problems are also possible and Boxers are prone to aortic stenosis and possibly other cardiac conditions. In addition, other respiratory diseases are possible, especially in a dog in which you do not have a complete history of where it might have been or what sort of medical care it may have had. An early diagnosis of heart or respiratory disease could markedly prolong your dog's life and also make him much more comfortable. Please have your dog examined by your vet.

Mike Richards, DVM

Vascular Ring Anomaly or Megaesohagus?

Q: We just bought a Rottweiler for Christmas. The puppy could not keep food down, eating vigorusly and then regergitating constantly. We took dog to vet and they X-rayed. He has megaesophagus. The vet said he has never heard of a puppy having this. The xray showed the esophagus larger than even an adult dog with megaesophagus. The Vet suggested there is nothing we can do except try different methods of feeding like small portions 3 to 4 times a day, and feeding very little. Try soft food, that didn't work, tried hard food, tried combination of soft and hard. He also said hold him upright for 5 minutes after eating. None of these things seem to work very well, although he is getting some nutrition. He is still pretty thin and seems to be asperating a little. He also is very hungry. Very hungry all the time and he eats so fast. None of the food seems to satisfy him. He was the runt of the litter. How can we get him to slow down eating and is there anything we can do for him so he is not so hungry all the time? A: In a puppy this young it would be very important to rule out a vascular ring anomaly constricting the esophagus. This is a situation in which the fetal blood vessels are still present when they should not be. The most common form of this is a persistent right aortic arch, but there are other possible ring anomalies. The vessel passes over the esophagus and captures it between the persistent aortic arch and other structures, constricting it. This can be cured surgically if many cases. In some cases, the esophageal motility is permanent impaired and it is necessary to feed liquid or semi-solid meals from a standing position for life. Please ask your vet if he or she can check for the ring anomalies and if not, consider referral to a cardiologist or veterinary referral center (like a vet school) where these can be rule out. Mike Richards, DVM

Bronchitis, Kennel Cough or CHF?

Q: Three years ago our 13 year old male cocker spaniel was treated for what the vet thought was bronchitis. His cough has never ceased. We took him to a new vet who stated he has congestive heart failure and placed him on furosemide. Thanksgiving week he was groomed at a new pet store. Several days later his cough became worse and the symptoms appear to be what is described as kennel cough. The vet listened to his heart and took an x-ray of his chest. He stated the heart murmur is worse and put him on Vasotec for his heart, Brethine for the cough, and continued the furosemide. The cough continues and the meds seem to being having very little effect at this time. Any suggestions? A: It is likely that your cocker does have heart problems, as very many cockers his age do. On the other hand, it is also very likely that the persistent cough is due to respiratory system problems rather than a heart problem. One common cause of persistent coughing is a collapsing trachea problem. This can be hard to diagnose and can also be pretty difficult to treat. Chronic bronchitis, allergic airway disease and other respiratory problems are also possible. Once in a while, the heart will enlarge enough to put pressure on the trachea or large bronchi and even though treatment is working the pressure remains, producing a chronic cough. Sometimes it is necessary just to use a cough suppressant to control this. It is hard to be sure what to do when there is one obvious problem but it isn't responding to treatment as expected. You should let your vet know that the problem persists and perhaps schedule a recheck visit. If your vet can't get the problem to resolve, you might inquire about referral to a veterinary cardiologist or internal medicine specialist. In many areas of the country it is easy to find a specialist with your vet's help. Good luck with this, Mike Richards, DVM