Case Study

Advanced dilated cardiomyopathy (DCM) in a 4 year old MN Boxer dog

A 4-year-old MN Boxer was presented for abdominal distention, labored breathing, edematous rear legs, and cachexia. The dog was being treated with Lasix but had been discontinued by the owner,

A 4-year-old MN Boxer was presented for abdominal distention, labored breathing, edematous rear legs, and cachexia. The dog was being treated with Lasix but had been discontinued by the owner,

Sonographic Differential Diagnosis

The echocardiogram is consistent with dilated cardiomyopathy with marked left atrial enlargement and an episode of heart failure. The condition appears well advanced at this time with the degree of structural change seen here and the ventricular arrhythmia puts the dog at risk for sudden death. This condition is most often idiopathic in origin but can also be seen with nutritional deficiencies such as taurine deficiency

Image Interpretation

The left atrium is markedly enlarged in size. All valves viewed appear normal. The left ventricular cavity is markedly dilated in diastole (6.0 cm) and systole (5.3 cm) with a depressed fractional shortening (12 %) consistent with myocardial failure. The left ventricular walls are thinned (0.9 cm septal wall and 0.9 cm free wall). The right ventricle is moderately dilated and the right atrium is moderately enlarged in size. The main pulmonary artery appears prominent in comparison to the aorta. The pulmonary artery velocity is normal at 0.8 m/sec. There is moderate mitral and tricuspid regurgitation as well as trace pulmonic insufficiency on Doppler exam. There is a moderate volume of pleural effusion and no pericardial effusion or evidence of neoplasia on this exam. The heart rate is measured at 120 to 136 bpm and a sinus rhythm with frequent single and paired, uniform VPCs are seen on an ECG run during the exam.

DX

Advanced DCM

Comments

Blood and plasma taurine levels can be considered to see if there were a nutritional component to the condition. If the dog were being fed an unusual, protein restricted or lamb-based diet, this can be switched to a high quality senior or cardiac support diet. Taurine supplementation is also recommended at 500 mg PO BID. An abdominocentesis and thoracocentesis are recommended as clinically warranted to relieve the effusion and improve respirations. The lasix can be restarted at 75 mg PO TID for 3 to 5 days and then tapered over a few days to a maintenance therapy, perhaps 50 mg PO BID or whatever is the lowest dose that will control the clinical signs. Pimobendan is recommended at 7.5 mg PO BID. Once the dog has improved, enalapril or benazepril can be added at 10 mg PO SID and increased to 20 mg PO SID after a week if it is well tolerated. If the ventricular arrhythmia were persistent, mexiletine can be added at 150 mg PO BID to TID to suppress it.