INTERATRIAL SEPTUM PENETRATION

A method is provided including inserting a catheter into a right atrium and advancing a distal portion of the catheter toward a roof of the right atrium. A flexible longitudinal member is deployed from the catheter, such that a deployed portion of the flexible longitudinal member is loop-shaped. The deployed portion of the flexible longitudinal member is brought into contact with a single stabilization site located on the roof of the right atrium, between the roof and an interatrial septum, or on the interatrial septum superior to a fossa ovalis. A needle is deployed from the catheter and brought in contact with a hole site on a surface of the interatrial septum outside the fossa ovalis. A hole is formed through the interatrial septum at the hole site with the needle. The deployed portion of the flexible longitudinal member is withdrawn toward the catheter. Other embodiments are also described.