A tissue closure device and a treatment method for closing an opening in a tissue wall are described. The tissue closure device comprises a heating element and a removable anchor having an anchor shaft and an occluding element at or near a distal end of the anchor shaft. The occluding element of the anchor is configured to be expanded and collapsed. The treatment method comprises introducing the occluding element of the anchor into a body canal through an opening in a tissue wall of the body canal, and deploying the anchor such that the occluding element expands to temporarily occlude the opening in the tissue wall. The tissue region surrounding the opening is then heated to cause shrinkage of collagen-containing tissue, thereby contracting the opening in the tissue wall. When a predefined trigger associated with the treatment method is met, the anchor is automatically undeployed and retracted from the body canal.
