Abstract: Disclosed herein is a catheter comprising: a first portion having a proximal end and a distal end, a second portion having a proximal end and a distal end, and a third portion having a proximal end and a distal end; wherein the first and the second portions comprise an outflow lumen; wherein the third portion comprises an inflow lumen and the outflow lumen; wherein the first portion has a helical portion having a first length and extending from the distal end of the first portion toward the distal end of the second portion; and wherein the catheter is configured to be inserted into a patient body such that the first portion penetrates an atrial septum to extend into a left atrium to assist with systemic perfusion with oxygenated blood. Also disclosed are septum fixation and docking assemblies, and the systems are using the same.