Case Study

Hypertrophic cardiomyopathy (HCM) with myocardial failure and tachycardia in a 1 year old MN DSH cat

A 1-year-old MN DSHcat with a history of cardiac disease that was being treated with Plavix, enalapril, pimobendan, furosemide, and atenolol was presented for evaluation of weakness and dyspnea.

Physical exam: tachycardia (200-400bpm) and a grade III/VI heart murmur

A 1-year-old MN DSHcat with a history of cardiac disease that was being treated with Plavix, enalapril, pimobendan, furosemide, and atenolol was presented for evaluation of weakness and dyspnea.

Physical exam: tachycardia (200-400bpm) and a grade III/VI heart murmur

Sonographic Differential Diagnosis

1.) Hypertrophic Cardiomyopathy – early onset, LV/RV involvement
2.) Myocardial Failure – profound
3.) Supraventricular Tachyarrhythmia – suspected
4.) CHF – historical

Image Interpretation

The left ventricular wall thicknesses are now moderately to severely thickened with myocardial failure. The myocardium is diffusely hyperechoic. The papillary muscles are at least moderately hypertrophied. The left atrium continues to be moderately enlarged in size, objectively and subjectively (La:Ao 1.84). There continues to be RV concentric hypertrophy, however this is much less notable compared to the left ventricle. The right ventricle also demonstrates myocardial failure, subjectively. Spontaneous echogenic contrast or atrial thrombi are not visualized in either atria. The IVS and atrial septum appear intact grossly in the images submitted. All valves appear normal grossly. Notable regurgitation is not visualized across any valves. There is normal, laminar flow across the aortic valve. There is a supraventricular tachycardia with HRs varying between 260-300bpm. The previously noted right bundle branch block/right axis shift is again visualized.

DX

1.) Hypertrophic Cardiomyopathy – early onset, LV/RV involvement 2.) Myocardial Failure – profound 3.) Supraventricular Tachyarrhythmia – suspected 4.) CHF – historical

Outcome

Patient’s echocardiogram is dramatically different today with the development of moderate to severe LV concentric hypertrophy and horrible myocardial failure. The other changes of RV concentric hypertrophy with myocardial dysfunction and biatrial enlargement remain. The changes to the LV indicate the patient has early onset, very malignant HCM. Patient was euthanized.

Clinical Differential Diagnosis

Progressive heart disease – cardiomyopathy (dilated, hypertrophic), congenital (valve stenosis/dysplasia, atrial/ventricular septal defect)
Endocarditis, myocarditis