Pet Paws Physio: Rehabilitating Mobility in Senior Dogs
May 31, 2024
Did you know that around 10% of dogs visiting veterinary clinics are diagnosed with heart issues, and this figure rises to over 25% in dogs over 10 years old? Certain breeds are more prone to heart disease, making early detection and vigilance crucial.
In this feature article, we will explore the signs of heart-related problems in senior dogs, common heart diseases, and practical steps you can take to support your dog's heart health. Senior Paws consulted with experienced veterinarian Dr. William Smith to delve into the heart health issues commonly seen in senior dogs.
William Smith
According to veterinary clinic data, about 10% of visiting dogs are diagnosed with heart disease. This percentage increases significantly with age. For instance, in dogs over 10 years old, the incidence rises to 25%. In small breeds, about 10% of dogs aged 5 to 8 have heart disease, while 20-25% of dogs aged 9 to 12 are affected. For dogs over 13 years old, the prevalence reaches 30-35%. Understanding the stages of heart failure helps dog parents prepare for the journey ahead if their dog is at risk or has been diagnosed with heart disease.
Heart failure in dogs progresses through five stages:
- Stage A: Dogs are predisposed to heart disease due to breed factors but show no clinical symptoms and do not require treatment. Initially high-risk, they are classified as Stage A and typically progress to Stage B1 with age.
- Stage B1: Dogs have a heart murmur but no clinical signs of heart disease. Imaging studies reveal a normal-sized and shaped heart. Treatment is usually unnecessary at this stage.
- Stage B2: Dogs exhibit a heart murmur and an enlarged heart without clinical symptoms. Treatment is recommended at this stage to prevent further progression.
- Stage C: Dogs show clinical symptoms of heart failure, such as coughing and reduced exercise tolerance. Imaging confirms an enlarged heart, indicating the onset of congestive heart failure. Aggressive treatment is necessary at this point.
- Stage D: Dogs continue to experience severe heart failure symptoms despite treatment. One significant issue at this stage is the inability to sleep properly due to fluid buildup in their lungs, causing frequent coughing and waking. This indicates severe discomfort and significantly impacts their quality of life.
What are common heart diseases in dogs?
The two most common heart diseases in dogs are Mitral Valve Disease (MVD) and Dilated Cardiomyopathy (DCM). MVD primarily affects small to medium-sized dogs, while DCM is more common in large breeds.
1.Mitral Valve Disease (MVD) in small to medium sized dogs:
MVD is particularly prevalent in small dogs. It is characterized by nodules forming on the mitral valve, affecting its function, leading to blood regurgitation and a heart murmur. However, the presence of a heart murmur does not necessarily indicate congestive heart failure; it simply means there is an abnormality in the heart's structure. Several small and medium-sized breeds are especially prone to Mitral Valve Disease (MVD), including:
- Cavalier King Charles Spaniels
- Maltese
- Dachshunds
- Poodles
- Toy Poodles
- Chihuahuas
- Pomeranians
- Yorkshire Terriers
These breeds are particularly susceptible as they age, making regular cardiac evaluations crucial, especially as they enter their senior years, to promptly detect and manage potential cardiac issues.
Cavalier King Charles Spaniels are famously predisposed to MVD. This breed is especially prone to developing heart disease at a very young age. Unlike other breeds where heart disease typically manifests around 8 or 9 years old, Cavalier King Charles Spaniels may show symptoms of MVD as early as 3 or 4 years old.
Around 50% of Cavalier King Charles Spaniels show signs of degenerative valve disease by the age of 5, and by 10, almost all Cavaliers exhibit this condition. While the incidence of MVD increases with age, not all dogs with valve abnormalities will progress to heart failure. Timely medication and environmental management can help delay the onset and progression of heart failure.
Aside from the mentioned genetic predispositions to MVD, certain breed dog owners should also be aware of another prevalent condition called Aortic Stenosis (AS), which is especially common in breeds like Boxers. AS is characterized by the narrowing of the aorta, which can disrupt blood flow. While AS may not always lead to heart failure, its severity depends on the degree of narrowing.
"If someone phones me up and says, ‘my dog's just collapsed, he's out on a walk and he's collapsed’, the next question is, ‘is it a boxer?’ It's usually aortic stenosis. As long as the narrowing isn’t too severe they are going to manage“
2.Dilated Cardiomyopathy (DCM) in Large Dogs
Compared to small breeds more prone to Mitral Valve Disease, Dilated Cardiomyopathy is more common in large breeds. DCM is a severe cardiac condition characterized by impaired cardiac muscle contraction, resulting in thinning of the heart muscle and enlargement of the ventricles. This condition renders the heart unable to effectively pump blood. Unlike MVD, which primarily affects the heart valves, DCM impacts the cardiac muscle itself, making it more severe than MVD with a poorer prognosis. Breeds Predisposed to DCM Several large breeds are particularly susceptible to DCM, including:
- Doberman Pinschers
- St. Bernards
- Irish Wolfhounds
- Great Danes
- Labradors
- Golden Retrievers （prone to have AS also)
Besides common heart diseases mentioned above, veterinarian William encountered some extremely rare cases that left a deep impression on him.
For instance, there was a large Samoyed dog suffering from severe arrhythmia (irregular heartbeat). However, with a different type of medication, the dog successfully regained its health. In another case, a small Westie had a persistently low heart rate of 40 beats per minute even during exercise, putting it at risk of sudden collapse. Normally, a dog's heart rate ranges between 60 to 140 beats per minute, depending on the dog's size.
Furthermore, a German Shepherd displayed rapid ventricular rates, necessitating cardioversion therapy to restore a normal rhythm. Despite contemplating additional interventions, the unfavorable prognosis prompted the decision by the owner not to proceed. These rare cases presented more challenging scenarios compared to the treatment of common heart issues like MVD and DCM in dogs.
How to Know if My Dog Has Heart Issues?
There are several signs that may indicate potential heart issues in dogs, including decreased exercise tolerance, changes in the respiratory rate during rest, and coughing. While coughing may also suggest respiratory problems, decreased exercise tolerance and an increased respiratory rate during rest could be early indicators of heart disease.
"The first question I always ask is, how long are their dogs' walks? If the dog owner says ‘20 minutes’, then I ask how long the dog was walking six months ago. If they say ‘40 minutes’, that's exercise intolerance. There is another situation the owner needs to be careful about. While a dog might go for an hour walk, the owner has to keep stopping and waiting for him to catch up."
Exercise intolerance is an early sign to watch for, although it can be subjective, especially considering factors like age and underlying conditions such as arthritis. Therefore, owners should assess changes in their dog's exercise habits relative to their baseline.
Monitoring the resting respiratory rate is a practical and reliable method for assessing a dog's heart health. A resting respiratory rate exceeding 30 breaths per minute may be a significant indicator of heart disease, especially for dogs with murmurs or enlarged hearts.
Dog owners can observe whether their pets exhibit rapid breathing or panting during rest. Panting differs from normal breathing and typically occurs when dogs attempt to cool down after exercise. Observing chest movements during rest can provide valuable information for evaluating a dog's respiratory rate and potential heart issues.
Cough actually is fairly late. By the time they're coughing, you've certainly missed the B2 stage. So it's better to catch them before they cough or earlier.
If owners can detect these symptoms early and seek veterinary care, there is a good chance of extending the dog's lifespan through appropriate medication and regular check-ups.
Treatment for Heart Disease in Dogs
When treating heart diseases in dogs, such as mitral valve disease (MVD) and dilated cardiomyopathy (DCM), four main medications are commonly used,
1. Pimobendan:
Pimobendan increases the force of heart contractions, making it particularly useful for treating DCM, and it is also effective for MVD.
2. Benazepril:
Benazepril is an angiotensin-converting enzyme inhibitor (ACEI) that helps dilate blood vessels, making it easier for blood to circulate throughout the body. This medication counteracts the body's natural response to constrict blood vessels when the heart isn’t pumping efficiently.
If you've been attacked by a lion and you're losing blood, your body's response is to contract the blood vessels to preserve your circulation and stop you from bleeding out. That works fine if a lion has attacked you. But if you're old and your heart isn't working properly, that response is unhelpful.”
3. Furosemide:
Furosemide is a diuretic that helps reduce excess fluid in the body, particularly in the lungs, which can alleviate coughing associated with heart disease. When the heart isn’t pumping fluid properly, it tends to accumulate behind the heart, leading to coughing.
One reason why dogs with heart disease cough, is if there's fluid in the lungs, and the diuretics then have to get rid of that excess fluid.”
4. Spironolactone:
Spironolactone is a potassium-sparing diuretic that also helps remove excess fluid, reducing the workload on the heart.
However, veterinarians often face the challenge of striking a balance between avoiding over-treatment and providing necessary care. Early identification of issues is important to optimizing treatment and improving the dog's overall health. Typically, initiating treatment around B2 stage is considered the most appropriate time.
When people know their dog has heart disease, if it's a small dog and they catch it early, the dog can probably live another two or even three years, certainly, as long as they're taking the medication and they can do very well."
William also referred to a specific study that compared the survival time of dogs with heart disease receiving medication versus those without. In this study, dogs in the B2 stage of heart failure, showing signs such as a heart murmur and heart enlargement but no clinical symptoms, were divided into two groups: one receiving treatment and the other not.
The study found that the average survival time for dogs receiving treatment was around 300 days, while those without treatment had an average survival time of only about 160 days, roughly half as long. This suggests that without treatment, dogs with early-stage heart failure may live around 6 months, but with treatment, their life expectancy could extend to 1 or 2 years.
How do I care for my dog with heart diseases?
Caring for dogs with a tendency towards heart disease or those already on medication requires careful management and observation by the owner. Here are detailed recommendations:
1. Regular Health Check-ups and Medication Management
For puppies, owners don't need to be overly concerned or restrict their activities, even if they have a predisposition to heart disease. An annual health check-up is sufficient to detect any potential health issues early on.
As the dog ages, regular health check-ups become even more important, especially if symptoms of heart disease appear. To evaluate a dog's heart condition, the examination might involve auscultation, X-rays, or blood pressure measurements. In some cases, echocardiography might be necessary depending on the situation.
For dogs already on heart disease medication, ensure they take their medication on time and follow the veterinarian's instructions for treatment. After starting medication, it is recommended to have a check-up every three months to monitor the condition and adjust the medication as needed.
2. Exercise Supervision
For dogs undergoing treatment for heart disease, exercise should be supervised to a reasonable amount. Observe the dog's exercise tolerance, and reduce the exercise level if the dog starts panting or showing signs of fatigue.
3. Temperatures and Environment Management
Older dogs, especially those with heart disease, are highly sensitive to temperature changes. Avoid exercising them in hot weather, particularly during summer. Ensure they rest in a cool environment to prevent overheating and excessive panting, which can strain their bodies. Additionally, if you're taking your senior dog to the groomer, ensure they refrain from using drying boxes to reduce the risk of overheating for the dog.
King Charles Spaniels, in particular, are prone to respiratory issues exacerbated by heat. Despite not experiencing extreme temperatures, they can still suffer from respiratory failure due to excessive panting.
“For a few years, every summer, we've got a couple of King Charles in with us, where they had heart disease, but they weren't really dying of heart disease. They were dying of respiratory failure because of the panting. So they were panting all night, and the muscles got actually exhausted. They just can't work anymore.”
It is also advisable to avoid outdoor activities during midday or high-temperature periods. It's best to walk the dog in the early morning or evening, or choose places with water where the dog can cool down, and never leave the dog in a car during summer.
I remember one dog died from it. The owner he's gone off from the car to a message and he got distracted. He came back 15 minutes later and the dog was in a bad way. It can happen very fast. About 20 degrees Celsius is the most dangerous temperature because we don't feel it's hot, but it’s hot for them."
4. Health Diet
For small to medium-sized dogs, consider switching to senior dog food around the age of 10, and for large dogs, around 7 years old. These foods typically contain lower sodium levels, alleviating strain on the heart. Choose low-sodium options to alleviate cardiac pressure and avoid feeding seasoned human food. For small to medium-sized dogs, consider transitioning to senior dog food at around 10 years old, and for larger dogs, around 7 years old. These foods typically have lower sodium levels, which can be easier on the heart. It's best to avoid giving your dog seasoned human food. Instead, discuss with your veterinarian about your dog’s diet, including appropriate supplements, such as fish oil, tailored to its health condition.
5. Symptom Monitoring
Owners can monitor their dog's condition by regularly measuring and recording the resting respiratory rate at home. If the dog suddenly collapses and has a purple tongue, it is urgent to seek veterinary care immediately. Prompt diagnosis and treatment are essential in such cases.
6. Emergency Transportation
Dogs with DCM are particularly prone to heart attacks. These dogs can collapse suddenly due to electrical abnormalities and arrhythmias in the heart, often without warning while they are active. If a dog with heart disease is losing oxygen and needs to be transported to the vet, it is important to carry them in the correct position. Lift the dog with its head slightly higher than the back end to ensure that fluid in the lungs does not press further on the heart. Transport the dog sloped upright, not vertically, with their chest elevated. This position helps them breathe more easily during transportation.
Although dog parents might be concerned about their dog’s heart condition, and might restrict their activities out of worry, they may inadvertently diminish their spirits. William extends a gentle encouragement to dog parents facing the challenges of caring for fur babies with heart disease.
“Don't worry too much. Don't let it affect the dog's quality of life. The aim of the medication is to give the dog the best quality of life for as long as they can have.Owners should keep the exercise to a reasonable level, but the point of the treatment is to allow the dogs to enjoy themselves as much as they can.”
With love, care, and proper treatment, these dogs can continue to experience joy and companionship, bringing comfort and fulfillment to their dedicated dog parents.
