A method for positioning an intravascular catheter may include inserting the intravascular catheter into a venous system of a patient, wherein the catheter includes a plurality of electrodes, and multiple electrodes of the plurality of electrodes are configured to emit electrical signals； positioning a distal portion of the catheter in a first position； using one or more electrodes of the plurality of electrodes to acquire an ECG signal； based on the acquired ECG signal, adjusting the distal portion of the catheter to a second position different from the first position； identifying at least one first electrode of the plurality of electrodes to stimulate a first nerve； identifying at least one second electrode of the plurality of electrodes to stimulate a second nerve； and stimulating at least one of the first and second nerves to cause a contraction of a respiratory muscle.
