2008 Radiology Exam - Ultrasound Case 2

History: A 18 month old female spayed Labrador retriever presented for a grade 4/6 heart murmur first noted at 8 weeks of age. The murmur became worse after a canoeing accident in which she almost drowns. The fractional shortening was 42% (normal range >25%). The e point septal separation was .10 cm (<.6 cm is normal). The ratio of the left atrium to the aorta was 1.46 (<1.3 is normal). Velocity measured was 4.2 m/s with a pressure of 74mmHg.

Instructions for ultrasound cases:

• Don’t discuss ultrasound artifacts unless prompted.
• Describe the abnormal ultrasound observations.
• List a ranked differential diagnosis.
• Case management in this section may not be limited to other imaging modalities. Additional procedures which would assist in the final diagnosis of these cases may be more appropriate to discuss than other imaging modalities.

Observations:

• Overall left ventricle larger than right ventricle, subjective thickening of interventricular septum and left ventricular free wall
• LA/ao ratio mildly increased
• Abnormal high velocity at aortic valve
• Narrowing of left ventricular outflow tract

Synthesis: Aortic stenosis: velocity 4.2 m/s pressure 74mm Hg

Case management: monitor for signs left heart failure, arrhythmias, and infections prone to endocarditis