Chihuahuas are prone to heart diseases, such as defective heart valves. A diseased heart has to pump harder, so it gets bigger and weaker. The condition is compounded for tiny pups. The Chihuahua's heart management regimen is effective when your dog is breathing slower and resting without reluctance.
Heart Specific Medications
A heart-specific medication regimen is the most common management for a dog's heart enlargement. Medications are administered by milligrams per kiligram of the dog's weight, so a Chihuahua's dosage will be smaller than that for larger breeds. The most common medications to improve heart function are ACE inhibitors, digoxin, calcium channel blockers and beta blockers. ACE inhibitors delay the onset of heart failure by slowing the heart, so the workload of the heart is reduced. Calcium channel blockers and beta blockers keep the heart beating at a normal pace with regular patterned heartbeats. Digoxin corrects irregular heartbeats, but it also improves the contraction strength of the heart so circulation to your Chihuahua's body improves. If you ever doubt the amount of medication prescribed for your dog, confirm the dosage with your Chihuahua's veterinarian. Too much medication could be fatal for such a small breed.
As your Chihuahua's circulation diminishes, you may notice fluids building up in the dog's body -- the legs may swell, and the abdomen may distend. The swelling will be more noticeable on a short-haired Chihuahua. Other symptoms of fluid retention are difficulty breathing and coughing. If your veterinarian listens to your Chihuahua's lungs with a stethoscope, he may hear fluids since the hearts inability to pump effectively is causing a back flow of fluids into the lungs. The most commonly used diuretic is furosemide. This drug can cause a Chihuahua to lose excess fluids, so you'll be taking the dog outside to pee a lot. Since these dogs are so small, carrying your Chihuahua outside instead of having him walk is one way to reduce the load on his heart.
A dog's diet does not play as significant a role for treating heart disease as it does for humans. However, a low-sodium diet is still recommended. Your Chihuahua's veterinarian can help you determine the max intake of sodium for your dog based on his weight and condition. Several over-the-counter dog foods exist, as well as dog foods offered through a veterinarian with reduced sodium levels. If your dog is taking a diuretic, your veterinarian will monitor potassium levels and give a potassium supplement if levels are low. Do not give potassium supplements unless advised by your doctor. Potassium has a small safe range, and an incorrect dose of excess potassium, especially with an already diseased heart, can be lethal for such a tiny breed.
Infective endocarditis is an infection of the heart that's usually caused by bacteria, but it can also be caused by a fungus. The infection can cause enlargement of the heart and is treated with antibiotics. As with all medications, dosage must be tailored to the Chihuahua's small size. Your vet will conduct a blood culture and start your dog on broad-spectrum antibiotics until the results of the cultured blood are apparent. Once your veterinarian knows the specific cause of the infective endocarditis, she will likely switch the antibiotics to a medication that fights the specific infective agent.
Melissa McNamara is a certified personal trainer who holds a Bachelor of Arts in journalism and communication studies from the University of Iowa. She writes for various health and fitness publications while working toward a Bachelor of Science in nursing.