擴張型心肌病（DCM）：原因、症狀與治療
DCM是一種嚴重心臟疾病，心肌變弱和擴大。了解與飲食的關聯、風險品種和治療選擇。
Dilated cardiomyopathy (DCM) is a disease of the heart muscle in which the heart becomes enlarged, thin, and weak, losing its ability to pump blood effectively. It is the second most common heart disease in dogs (after mitral valve disease) and is particularly prevalent in large and giant breeds. In recent years, concerns have emerged about a possible link between grain-free diets and DCM in breeds not traditionally predisposed. Understanding DCM, recognizing early signs, and getting timely treatment can significantly extend your dog's life.
- DCM causes the heart to enlarge and weaken — it cannot pump blood effectively
- Large breeds (Doberman, Great Dane, Boxer, Irish Wolfhound) are genetically predisposed
- Recent research suggests grain-free and legume-heavy diets may contribute to DCM in some dogs
- Early signs: exercise intolerance, increased breathing rate, fainting episodes
- DCM progresses to congestive heart failure if untreated — fluid builds up in the lungs
- Early detection with echocardiography allows treatment that can extend life by months to years
What Is DCM?
In DCM, the heart muscle (myocardium) progressively weakens and stretches. The heart chambers enlarge (dilate) and the walls become thin. As the heart weakens, it cannot contract forcefully enough to pump adequate blood to the body. The heart tries to compensate by beating faster, which eventually worsens the problem. Blood backs up into the lungs, causing fluid accumulation (pulmonary edema) — this is congestive heart failure. DCM can also cause dangerous arrhythmias (irregular heartbeats) that may lead to sudden death.
Breeds at Risk and Dietary Concerns
Genetically predisposed breeds: Doberman Pinscher (highest risk — up to 60% may develop DCM), Great Dane, Boxer, Irish Wolfhound, Newfoundland, Saint Bernard, Cocker Spaniel, and Golden Retriever. Diet-related DCM: in 2018, the FDA began investigating reports of DCM in dogs eating grain-free diets, particularly those high in legumes (peas, lentils, chickpeas) and potatoes. Breeds not traditionally at risk (Golden Retrievers, mixed breeds) developed DCM that sometimes improved with diet change. The relationship is still under investigation, but many veterinary cardiologists recommend avoiding boutique, exotic-ingredient, and grain-free (BEG) diets.
Recognizing the Signs
Early DCM often has no visible signs — this is why screening is important for at-risk breeds. As the disease progresses: exercise intolerance (your dog tires more easily on walks), increased resting breathing rate (above 30 breaths per minute at home), coughing (especially at night or after exercise), fainting or collapse (syncope — from arrhythmias or poor cardiac output), distended abdomen (from fluid accumulation), rapid or irregular heartbeat. In Dobermans, DCM can progress silently — the first sign may be sudden death from an arrhythmia.
Diagnosis and Treatment
Diagnosis: echocardiography (ultrasound of the heart) is the gold standard — shows chamber enlargement and reduced contractility. Additional tests: ECG (detects arrhythmias), chest X-rays (show heart size and lung fluid), blood pressure, and cardiac biomarkers (NT-proBNP). Treatment: pimobendan (Vetmedin) — the cornerstone medication that improves heart contractility and reduces workload. ACE inhibitors (benazepril, enalapril) — reduce blood pressure and cardiac remodeling. Diuretics (furosemide) — remove fluid from lungs if CHF is present. Anti-arrhythmic medications if arrhythmias are detected. Diet change: if diet-related DCM is suspected, switch to a grain-inclusive, WSAVA-compliant diet. Taurine supplementation may help in some cases.
- Your dog is tiring more easily during walks or play
- Your dog's resting breathing rate is consistently above 30 breaths per minute
- Your dog has fainted or collapsed, even briefly
- Your dog is coughing frequently, especially at night
- Your dog's abdomen appears swollen
- Your dog is eating a grain-free diet and you want cardiac screening
Royal Veterinary Center provides cardiac screening for at-risk breeds including echocardiography, ECG, blood pressure monitoring, chest X-rays, and cardiac biomarker testing (NT-proBNP). We manage DCM with evidence-based medication protocols including pimobendan and ACE inhibitors, and offer dietary counseling for dogs on grain-free diets. Regular cardiac screening can detect DCM before symptoms appear. Call +853 6677 6611.
+853 6677 6611