A catheter includes a catheter body, a pump assembly and a cannula. The pump assembly can be disposed at a distal end of the catheter body and has a distal portion. The cannula can be coupled to the distal end portion of the pump assembly and can include a proximal cannula portion and a distal cannula portion. The distal cannula portion has an approximately helical shape which can allow the cannula to be inserted into a patient's right heart and pump blood therethrough. In certain implementations, the distal tip of the helical shape has a slight bias relative to the main helix to further facilitate delivery of the device. In certain applications this bias is toward the central axis of the helix.
