This disclosure is directed to a catheter having an ellipsoidal basket-shaped electrode assembly at the distal end of the catheter body formed from a plurality of spines with electrodes. The ellipsoidal basket-shaped electrode assembly has a first deployed expanded configuration having a first area of electrode coverage and a first electrode density, a second deployed expanded configuration having a second area of electrode coverage less than the first area and a second electrode density higher than the first density, and a collapsed configuration wherein the spines are arranged generally along a longitudinal axis of the catheter body.
