Figure 5. Trefoil hook to grasp the apical portion of the septal bulge Stabilizing the position of the septal bulge with a trefoil hook retractor makes myectomy results more predictable and lessens the chance of ventricular septal defect. The trefoil hook retractor with a long handle is introduced deeply into the ventricular cavity and imbedded into the farthest portion of the septal bulge with an orientation between the right coronary ostium and the right and left coronary commissure . When drawn forward, a larger bulge in the septal muscle is created which lends itself to resection. The trefoil hook serves two purposes. It defines in the anterior-posterior direction the point towards which the #15 scalpel blade is pushed and it stabilizes the muscle to be resected and prevents it from being pushed out and away from the blade and surgeon. Two parallel incisions are made into the bulge with the knife directed towards the prongs of the hook; the first is below the right coronary ostium and the second below the left and right coronary commissure.