Case Study

Stage B2 Valvular Disease Left Atrial Enlargement Mitral Prolapse in a 13 year old Chihuahua Dog

A 13-year-old NM Chihuahua with a history of congestive heart failure was presented for evaluation. Current therapy is Enalapril bid. occasional cough was present at exercise.

A 13-year-old NM Chihuahua with a history of congestive heart failure was presented for evaluation. Current therapy is Enalapril bid. occasional cough was present at exercise.

Sonographic Differential Diagnosis

Ruptured chordae tendinae. Myocardial insufficiency owing to severe left atrial enlargement and left sided overload. Concurrent tricuspid insufficiency. Recommend adding Lasix at 2-3 mg/kg b.i.d., Spironolactone 1-2 mg/kg s.i.d., ace inhibitor continuation at 0.5 mg/kg b.i.d. and Pimobendan at 0.25 mg/kg b.i.d. This patient is at risk for sudden death. ECG and blood pressure measurements are strongly recommended. This is consistent with stage C1 valvular disease. Recheck echocardiogram in one month

Image Interpretation

The echocardiogram for this patient presented a left atrium of excessive size with anechoic content as did the corresponding LA:AO ratio. No evidence of “smoke” or thrombotic activity was noted. The atrial septum was deviated toward the right atrium without evidence of dilation or contraction. Flail mitral valve leaflet was noted with ruptured chordae tendinae. Severe mitral valve insufficiency was noted. The left ventricle demonstrated prominent volume, normal septal and free wall diastolic thicknesses, and papillary integrity. Ventricular function was deemed adequate to hyperdynamic expressed by the fractional shortening measurement listed below. The aortic outflow tract revealed direct laminar flow along the ventricular septum with normal outflow velocity through linear valve leaflets with adequate extension, closure and uninterrupted motion. No evidence was found regarding valvular insufficiency or post stenotic dilation. Periaortic tissue was uniform and of normal echogenicity. No inconsistencies were revealed regarding the presence of an aortic body tumor or chemodectoma. The right atrium was subjectively assessed and found to be uniformly smaller than the left atrium without evidence of dilation or contraction. No neoplastic evidence was visualized here or into its extension of the right auricle. The tricuspid valve insufficiency was also present. The right ventricle demonstrated normal size (1/3 diameter of the left ventricle), morphology, and kinetic activity. No evidence of heartworm or infiltrative disease was noted. The pulmonic outflow tract presented free of dilation (1:1 PA/AO ratio), adequate laminar flow, no evidence of insufficiency, and free of visible heartworm activity. The myocardial insufficiency was noted. Endo, epi, pericardial and pleural tissue was uniformly hyperechoic to the myocardium without the presence of effusions. The diaphragm was visualized as uniform without interruption. Periodic arrhythmia was noted in this patient. Mitral insufficiency 4.9 m/sec. Tricuspid insufficiency 2.56 m/sec.

DX

Stage B2 Valvular Disease Left Atrial Enlargement and Mitral Prolapse

Outcome

The patient’s medication was adjusted to initiate triple therapy Pimobendan, Lasix, Enalopril to maximum dose of ace-i and adding spironolactone. Prognosis guarded.

Clinical Differential Diagnosis

Progressive mitral/tricuspid insufficiency, chordae tendinae rupture, myocardial weakness, myocarditis, pericardial effusion

Sampling

None