Small Animal Services: Cardiology Degenerative Mitral Valve
What is Myxomatous or Degenerative Mitral Valve Disease?
Canine myxomatous or degenerative mitral valve disease (M or DMVD) primarily affects older, small to medium size dogs, although any dog can be affected. Degenerative changes thicken the valve, causing it to leak. When the disease and leakage progress, the heart enlarges. Predisposed breeds include Cavalier King Charles Spaniels and Dachshunds – although the genetics are being investigated, the disease is very common in small breed dogs as they age. Though many dogs are affected in their later years, only about 25% of those with MMVD experience clinical signs of congestive heart failure (CHF, or fluid build-up within the lungs).
Degenerative Mitral Valve Disease
How is DMVD diagnosed?
A distinctive heart murmur is the most common sign of mitral valve disease. The murmur is caused by the valve leak. Chest X-rays or an echocardiogram (ultrasound of the heart) or both are used to assess the severity of the leak, and the extent of heart enlargement.
How is DMVD treated?
Treatment depends on the severity of the valve leak. Mild leakage with minimal or no heart enlargement is typically monitored at regular intervals without treatment. Dogs with significant heart enlargement benefit from medication to delay the onset of CHF. Dogs that experience CHF require additional medication, and some dogs need to be hospitalized for heart failure treatment. Because medications control only the clinical signs of CHF and do not treat the primary valve problem, we are working on surgical methods to repair the valve itself. At this time, surgical treatment is not widely available, but the possibility of valve repair can be discussed with your cardiologist.
How is DMVD monitored by my veterinarian and my cardiologist?
Although an echocardiogram is often initially performed during the diagnosis, regular echocardiograms may not be needed, and chest x-rays may provide a more cost effective means of monitoring disease progression. Dogs that have experienced CHF are followed more closely with blood pressure and bloodwork, typically every 3-6 months or after medication changes.
How can I tell how my dog is doing at home?
Dogs with minimal heart enlargement should be treated as normal dogs, requiring only usual (annual or semiannual) monitoring. The first signs of CHF often include shortness of breath, exercise intolerance, or cough – these signs should prompt a call and usually a vet visit. In dogs that have experienced an episode of CHF, monitoring the breathing rate during sleep or rest provides a sensitive indicator of how they’re doing – normal is less than 36 breaths/min. The Cardalis phone app simplifies obtaining and tracking the breathing rate.
Is diet important?
While some salt restriction (e.g. avoidance of high salt treats) is ideal for most dogs with significant MMVD, and moderate salt restriction aids CHF treatment, it’s important that your dog’s appetite remains good, and his or her caloric and protein needs are met.
What is the prognosis with DMVD?
Many older dogs affected with MMVD will not have their lifespan limited by their heart disease. The rate of disease progression varies, but it most often takes years before clinical signs of CHF develop. After CHF develops, dogs are expected to continue to have an excellent quality of life with treatment, and most survive for an additional 12-18 months, although their survival time varies widely.
The NC State Cardiology Service supports numerous research projects aimed at building on what is already known about heart failure and at uncovering new knowledge about its causes, diagnosis and treatment…
Veterinary Cardiac Genetics
Are you interested in learning more about cardiomyopathies, (diseases of the heart muscle)? DNA testing is available for the following breeds: Feline HCM (Maine Coon, Ragdolls), or Canine cardiomyopathies (Boxer, Doberman.)
The NC State Cardiology service now offers a Holter (24 hour ambulatory ECG) program.
Go to the Cardiology Clinical Studies page for information on current clinical studies. Details include the study’s purpose, benefits for participating, and financial incentive information.
Hypertrophic Cardiomyopathy in Cats
Hypertrophic Cardiomyopathy (HCM) is the most prevalent feline cardiac disease. It is a primary disorder of the heart muscle characterized by thickening of the left ventricle. Learn more here…
Frequently Asked Questions & Resources
We operate primarily on a referral basis, with the patient’s primary veterinarian referring them to the NC State Cardiology Service by calling us to discuss the patient’s condition.
Referral is not required for second opinions, breed-related certifications for congenital heart disease, or treatment of heartworm infection. By speaking with the primary veterinarian prior to the appointment, we are often better able to determine the severity of the problem, which of our services the patient is likely to need, how soon the patient needs to be seen, and whether any of the other specialty services at the VH should be consulted. We will also discuss our policies and fees at the time the referral is made, and formulate a plan for communicating our findings to the primary veterinarian.
After the referral has been made, owners may call us to make the appointment. We will collect owner and patient demographic information, provide an estimate of charges, discuss some of the diagnostic procedures that may be required, and answer any questions the owner may have regarding the visit. In order to have the best chance of getting a complete diagnostic work-up done in one day, we try to schedule new patients in the morning between 9:00-10:30 every day except Thursday which is reserved for interventional cardiac catheterization or other semi-elective surgical procedures.
The average total cost for some uncomplicated common interventional procedures that we perform routinely are as follows:
- Pacemaker implantation (includes EMG workup): $2800-3000
- Balloon valvuloplasty (includes workup): $2800-3000
- Patent Ductus Arteriosus occlusion (includes workup): $2500-2800
- Heartworm Retrieval (canine/feline): $2200-2500
Information Needed for Initial Evaluation
- Brief description of the reason for the appointment with the Cardiology service, including all of the patient’s symptoms even those that may not seem significant.
- List of medications patient is receiving, including any over the counter drugs, herbs or metabolic supplements, as well as any problems the patient may be having with the medications.
When am I going to see a doctor?
Please note that our Interns and Residents (aka House Officers), are fully licensed doctors with the same education and credentials as a general practitioner. There will ALWAYS be a doctor in charge of and supervising all aspects of patient care at the VH. In many cases multiple specialists may consult on a patient should their expertise be required. Typically, a fourth-year student will first collect a detailed history and present this information to the doctor in charge. You will then have an opportunity to discuss things in detail with the doctor and together you and he/she will formulate a diagnostic and treatment plan.
My doctor introduced him/herself as an Intern or a Resident – what does that mean?
It is important to understand that every intern or resident at the VH is a fully licensed doctor with the same education and credentials as a general practitioner. Interns and residents have chosen to pursue additional, in-depth postgraduate clinical training and were selected by us in a highly competitive international application process. We think you are in great hands!
Examination: Generally, a 4th-year veterinary student will escort the client and patient into an exam room to take a complete history while they perform a physical examination on the patient. This will take approximately thirty minutes.
Review: The student will then leave the room for about fifteen minutes to consult with one of our faculty cardiologists. At this time, the student and the cardiologist will also review any diagnostic material that the referring veterinarian has sent. The cardiologist will then introduce him or herself to the client and examine the patient. New patients usually need to be left with us for the day to allow enough time to complete the diagnostic tests needed to evaluate the heart and cardiovascular system.
Diagnostic tests for patients suspected of having heart disease often include electrocardiography, echocardiography, radiography, and various blood tests. Patients may need to be lightly sedated to complete the evaluation, since several of these tests require the patient to be absolutely still for several minutes at a time.
Discharge: At the time of discharge from the hospital (usually between 4PM-6PM), the cardiologist will discuss the patient’s condition with the owner and answer any questions. We will also send home detailed written information about the physical findings, diagnostic test results, diagnoses, medications, and recommendations for ongoing care. A copy of these instructions will be faxed to the referring veterinarian.
While a patient is hospitalized, the cardiologist and student on the case will arrange mutually convenient times every day for the owner to call (or be available to be called) to get an update on the patient’s condition, and answer any questions that may arise. We will also arrange mutually convenient times for the owner to visit the patient, if desired.
You are a State facility, so why are your fees so high?
The VH is a not-for-profit health care center and receives less than 2% of operating costs from the the State of North Carolina. The majority of our operating costs are paid by client fees and donations. In fact, many of the state-of-the-art diagnostic and treatment options we offer are only possible because of generous gifts from our clients. Our fees are set to cover the balance of our operating costs, and we are always looking for ways to provide better service at lower cost. Total costs are comparable to those of veterinarian specialists in private practice.
If you do not have a primary veterinarian you can search for one here: North Carolina Veterinary Medical Association
Additional resources may also be found at the NC State College of Veterinary Medicine’s website.