History: Exercise intolerance. Grade III/VI left sided ejection-type systolic murmur.
There is moderate to severe right ventricular hypertrophy with notable hypertrophy of the right ventricular papillary muscles. There is also flattening of the interventricular septum, indicating that the right ventricular pressure exceeds the left ventricular pressure (> 120 mmHg). There is moderate to severe right atrial dilation. There is severe tricuspid insufficiency. There is doming of the pulmonic valve leaflets noted with aliased flow noted across the pulmonic valve orifice. The transpulmonary spectral Doppler velocity is approximately 5 m/sec, estimating a transpulmonary pressure gradient of 100 mmHg. There is moderate post stenotic dilation of the main pulmonary artery. The left ventricle subjectively appears underfilled, leading to subjective pseudohypertrophy of the left ventricle. There is no left atrial dilation noted.
Assessment: Severe pulmonic stenosis with severe tricuspid regurgitation, moderate to severe right atrial dilation and moderate to severe right ventricular hypertrophy.
Recommendations: Recommend referral to a cardiologist to perform a full congenital echocardiogram, which may include a bubble study to evaluate for any right to left shunting. Right heart catheterization with a pulmonic balloon valvuloplasty is the treatment of choice in cases of severe pulmonic stenosis (> 80 mmHg gradient across the pulmonic valve). However, in bulldogs and other bulldog type breeds (Pitbulls, French bulldogs), a left heart catheterization to evaluate the coronary arteries is advised to look for an aberrant coronary artery (R2A anomaly). In these cases, aggressive balloon valvuloplasty could rupture this coronary artery and cause sudden death and should be avoided.
Key hints: The right ventricle should normally be 1/3 the size of the entire heart; in this case, you can see that it is greater than half. To determine if right heart enlargement / right ventricular hypertrophy is caused from pulmonic stenosis or pulmonary hypertension (the two main causes), you need to evaluate the tricuspid regurgitant velocity and the transpulmonic velocity. If the TR velocity is elevated (> 3 m/sec), but the PV gradient is normal, this is consistent with pulmonary hypertension. However, if the TR velocity is elevated AND the PV velocity is elevated to the same degree, this is consistent with pulmonic stenosis. Most cases of pulmonic stenosis are primary valvular, with rare reports of subvalvular and supravalvular stenosis. Occasionally there is a dynamic component of the stenosis caused by significant right ventricular outflow tract hypertrophy, leading to a late peaking profile of the spectral Doppler flow profile.