Surgical septal myectomy is a procedure typically done for hypertrophic cardiomyopathy (HCM) where a portion of the hypertrophied interventricular septum (IVS) is resected. The basal portion of the IVS can lead to left ventricular outflow tract obstruction (LVOTO), limiting cardiac output and causing associated symptoms like dyspnea, lethargy, and organ dysfunction.
After central cannulation for cardiopulmonary bypass, administration of cardioplegia, and appropriate venting, an aortotomy is made. The surgeon will then inspect the aortic valve and resect a slice of the IVS several centimeters into the ventricular cavity down to the level of the papillary muscles. Secondary mitral valve chordae are often resected to reposition the mitral leaflet coaptation posteriorly to limit systolic anterior motion (SAM).
In this midesophageal long-axis TEE view, the first half of the video demonstrates HCM with SAM and LVOTO. The second half is post-septal myectomy. Because this procedure is more or less blind, there’s a risk of resecting too much IVS, resulting in a ventricular septal defect (VSD). With a VSD, color-flow Doppler would demonstrate systolic flow across the IVS in this midesophageal long-axis TEE view. Instead, the video shows diastolic flow emanating from the IVS following myectomy consistent with unroofed septal perforator vessels – an expected finding after coming off cardiopulmonary bypass.
