The Correct Answer is B!

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A 44 year-old man has a systolic murmur and symptoms of exertional dyspnea and light headedness. The cardiac catheterization traces show the left ventricular (LV) and aortic (Ao) pressures after a premature ventricular contraction (PVC).

What is the mechanism of the outflow tract obstruction?

  1. Dynamic left ventricular outflow obstruction of H
  2. Fixed valvular aortic stenosis
  3. Increased gradient due to acute severe aortic regurgitation
  4. Mid-ventricular obstruction of HCM

Answer Rationale:

In patients with left ventricular outflow obstruction, the etiology of the obstruction can be determined by the pulse pressure that occurs on the beat after a PVC. With dynamic LVO or midventricular obstruction, there is a decrease in pulse pressure on the post PVC beat. In severe acute aortic regurgitation, there should be a wide pulse pressure during NSR and after a PVC. In this patient, there is an increase in gradient but also an increase in pulse pressure after a PVC, indicating fixed obstruction.

1.  Source: "Comparative Analysis of Pre/Post Assessments of Live/Didactic Course Attendees when compared to Mico-Learning/Online Course Users., "Knowledge to Practice, 2017.

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