Anomalous Papillary Muscle Insertion Causing Dynamic Left Ventricular Outflow Tract Obstruction without Hypertrophic Obstructive Cardiomyopathy

Figure 2

Hemodynamic tracings at cardiac catheterization. (a) Simultaneously measured aortic and LV pressures using a dual lumen pigtail catheter demonstrate an 84 mmHg resting peak-to-peak gradient. The aortic waveform shows a spike-and-dome pattern, and the LV waveform is late-peaking. After premature ventricular contractions are provoked (black arrow), the postextrasystolic beat demonstrates a reduction in aortic pulse pressure with a worsening in peak-to-peak gradient to 160 mmHg (checkered arrow). This finding is consistent with dynamic LVOT obstruction. (b) Pullback tracing with the dual lumen pigtail catheter starting in the mid LV cavity (black arrow) and then being withdrawn to just beneath the aortic valve (checkered arrow) demonstrating normalization of the large gradient. This suggests that the site of obstruction is within the LVOT.

(a)

(b)