Small Animal Soft Tissue Surgery Q&A 21

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You are presented with a one year old, female Giant Schnauzer for its annual vaccinations. On auscultation of the chest you detect a murmur. Part of your diagnostic evaluation includes a selective right ventricular angiogram. The radiograph pictured demonstrates the lesion.

Question	Answer		Article
Name the cardiac lesion.	Subvalvular pulmonic stenosis with muscular infundibular stenosis. There is also poststenotic dilation of the pulmonary artery.		Link to Article
Describe the murmur you would hear with this type of lesion.	Crescendo–decrescendo systolic murmur heard best on the left side at the base of the heart.		Link to Article
What ECG findings would you expect with this lesion?	ECG changes would be consistent with right-sided cardiac enlargement and right axis deviation. Tall P waves, S waves greater than 0.35 mV in lead II and greater than 0.05 mV in lead I, presence of S waves in leads I, II, III and aVF, and deep Q waves (>0.5 mV) in leads I, II, III and aVF are consistent with right-sided cardiac enlargement.		Link to Article
What therapy would you recommend, and what would determine if medical or surgical therapy were indicated?	The decision between medical and surgical management of pulmonic stenosis is generally based on the pressure gradient between the right ventricle and the pulmonary artery. A catheter is placed through the right ventricle into the pulmonary artery, and pressures are monitored as the catheter is withdrawn through the stenosis. The pressure in the pulmonary artery is lower than that of the right ventricle because of obstructed flow. Surgery is recommended in adult dogs if right ventricular systolic pressure is 120 mmHg or greater (in immature dogs greater than 70 mmHg), or if the gradient across the stenosis is greater than 100 mmHg. No specific medical therapy is indicated for the management of pulmonic stenosis. Many dogs are asymptomatic and those with clinical signs generally have pressure gradients which warrant surgery. If left untreated, signs of right-sided heart failure develop and may be managed medically.		Link to Article