The invention relates to an anchor hook and methods of using the same for subannular anchoring of a transcatheter heart valve replacement, and in particular for an orthogonally delivered (side-delivered) transcatheter prosthetic heart valve having a annular support frame having compressible wire cells that facilitate rolling and folding the valve length-wise, or orthogonally to the central axis of the flow control component, allowing a very large diameter valve to be delivered and deployed to the mitral or tricuspid valve from the inferior vena cava or superior vena cava, or trans-septally to the mitral valve, the valve having a height of about 5-60 mm and a diameter of about 25-80 mm, without requiring an oversized diameter catheter and without requiring a delivery catheter to bend 90 degrees during deployment.