Apparatus and methods are provided for sealing a puncture through the wall of a patients heart into a heart chamber, e.g., at the apex of the heart into the left ventricle. A positioning member is advanced into the puncture until a positioning element thereon is disposed within the chamber, the positioning element is expanded within the chamber, and the positioning member is withdrawn until the expanded positioning element contacts the endocardial wall of the chamber. A cartridge carrying a solid sealant is advanced over the positioning member, and the sealant is deployed within the puncture, e.g., offset proximally from the endocardial wall, the sealant expanding upon exposure to fluid within the puncture to seal the puncture.
