Cat Disease: Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats. As the name suggests, it refers to the abnormal thickening of the ventricular wall, and excludes the factors and diseases that cause secondary cardiac hypertrophy. The cat disease is common in middle aged to older cats of either gender, with an average age of 5.5 to 6.5 years, and there are also clinically diagnosed cats with HCM at 3 months of age, but it is rare, and it is usually a pure breed with genetic predisposition Cat.
Many cats with HCM are diagnosed without clinical symptoms and abnormal medical history. To date, the most common discovery of HCM is physical examination during annual health checkups or diagnosis of other diseases. It is found due to auscultation of heart murmurs or galloping rhythms; sometimes an enlarged heart is suspected on X-ray examination. Some severe cases may have sudden death, and it was found to have HCM at autopsy. Sudden death of HCM cats can occur at any age, young cats are more common (<5 years old). A study showed that cats with congestive heart failure (CHF) in half of hypertrophic cardiomyopathy have predisposing factors (Rush et al 2002), the most common being infusion (28%), followed by anesthesia/surgery (25%) and The use of glucocorticoids (21%) is often given 1 to 2 weeks before the onset.
When congestive heart failure occurs, the typical symptoms are difficulty breathing, weakness, anorexia, vomiting, or weight loss. Sometimes the owner often cannot distinguish between coughing, vomiting and sneezing, especially when coughing up with mucus or hairballs. Cats with lung, airway, chest, or heart disease should be observed carefully the association between cough and vomiting in detail. If vomiting occurs only after coughing, gastrointestinal abnormalities are not the main cause. Syncope symptoms are uncommon. Only 10 out of 260 cats, about 4%, often occur after arrhythmia, severe congestive heart failure, or intracardiac thrombosis. Cats with arterial thrombosis often experience claudication, paralysis, and pain. The incidence of HCM is 12 to 17%. In the medical history investigation, it is necessary to ask whether there was an acute claudication before, sometimes temporarily, and sometimes acute mental or gastrointestinal symptoms when thrombosis occurs in the brain or gastrointestinal tract. Its occurrence has no obvious correlation with age, gender or breed. Other complaints may not be directly related to heart disease, such as dehydration, clinical symptoms caused by hyperthyroidism or renal failure, and other systemic diseases.
Diagnosis of Cat Disease:
Echocardiography is the most accurate tool for diagnosing HCM. To confirm HCM, there must be centripetal symmetry or asymmetric left ventricular hypertrophy, such as left ventricular wall thickening but with no other causes such as aortic stenosis, hypertension, or hyperthyroidism. Concentric hypertrophy is defined as the left ventricular end-diastolic free wall or septal thickness ≥ 6 mm, and the gray zone is 5.5 to 5.9 mm. Hypertrophy of papillary muscles can also be seen in cats with HCM, and usually develops into centripetal hypertrophy 6 to 12 months later. The size of the left atrium is important for the assessment of the severity of the disease. The dilation of the left atrium often indicates the risk of congestive heart failure or thrombosis, and heart failure assessment is required. It can usually be measured on the short-axis aortic cross-section of the right sternum and compared with the diameter of the aorta. The LA/AO ratio is often used to reduce the effect of body size on the parameters, but the effect of cats is relatively small. Red blood cell aggregation is likely to occur in the dilated left atrium or only in the atrial appendage, leading to differences in the autogenous echo of ultrasound. The difference in auto-echo is a blood clot precursor, which usually strongly suggests arterial thrombosis. Such cases require careful evaluation of thrombosis, especially in the left atrial appendage when the left atrium is dilated. Cats with thrombosis have a high probability of sudden death. The left atrial appendage is the place with the slowest blood flow in the left atrium, and also has small branched comb muscles, which is very conducive to thrombosis. Cats with autoechoic differences or intracardiac thrombi require anticoagulation therapy. The mitral valve systolic anterior movement (SAM) is a hallmark of HCM pathological features. It can be found on the cross-section of the left ventricular outflow tract on the long axis of the right sternum next to the two-dimensional ultrasound. Color Doppler is an effective tool for diagnosing mitral regurgitation and systolic ejection turbulence. Continuous Doppler can be used to measure the severity of left ventricular outflow tract obstruction. Using the modified Nuberli equation, pressure = 4v2, the pressure is less than 50mmHg in mild obstruction; the pressure is 50-80mmHg in moderate; more than 80mmHg is severe. SAM is a kinetic obstruction that can worsen ventricular contractility and tachycardia, and is relieved after the use of negative heart power and time-varying drugs, such as atenolol. Pulse Doppler detection of the mitral valve can be used to assess diastolic function. In cases of severely abnormal diastolic function, left atrial pressure is increased, ventricular stiffness is increased, and ventricular stiffness and filling restrictions will lead to a sharp decrease in early diastolic ventricular filling.
Treatment of Cat Disease:
Home care stage: The treatment of cat disease Hypertrophic cardiomyopathy is predominantly managed with medication and monitoring at home.
Medication: The treatment methods and commonly used drugs are mainly the following:
When arrhythmia and fast heartbeat occur, calcium channel blocker Diltiazem and beta-blocker Atenolol can be taken to relax the heart muscle and relieve the heart rhythm.
When cats have symptoms of congestive heart failure, the ACE inhibitor Enalapril (Enalapril) can be used to improve blood flow through the ventricles. In addition, since congestive heart failure often causes fluid retention, the diuretic furosemide (Furosemide) can be used to remove excess fluid from the body.
If a large amount of pleural effusion is found by X-ray examination and the breath has been compressed, the drainage method should be considered by puncture.
When cats have metabolic acidosis and hyperkalemia, sodium bicarbonate can be injected intravenously.
When left atrial hypertrophy occurs and flocs or clots are visible inside, it indicates that the risk of thrombosis is extremely high, and anticoagulant therapy such as aspirin, warfarin, and heparin can be used to delay and avoid the appearance of thrombosis (Anticoagulants can only prevent blood clots, and are not effective against already formed blood clots).
If a thrombus has formed, then thrombolytic agents are needed. Commonly used drugs are streptokinase, urokinase, and tissue plasminogen activator.
Because blood clots can cause extreme pain in cats, analgesics such as hydromorphone or hydromorphone should be given immediately after diagnosis to relieve pain.
The medication of this cat disease should be noted that the above drugs cannot be used without authorization and need to be used under the guidance of a professional veterinarian. For example, overdose of Diltiazem and Atenolol can cause bradycardia; Regular monitoring of renal function when using Furosemide; and anticoagulants and thrombolytic agents may cause bleeding complications.
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