High density flat balloon catheter

A pulsed field ablation catheter comprising:

• an elongate catheter shaft comprising a proximal end and a distal end, the elongate catheter shaft defining a longitudinal axis;
• and
• an expandable assembly, wherein the expandable assembly comprises:
• a balloon member comprising a top surface, a bottom surface, and an interior cavity, each of the top surface and the bottom surface comprising an outer facing layer and an inner facing layer;
• a top flexible framework disposed between the outer facing layer and the inner facing layer of the top surface of the balloon member;
• a bottom flexible framework disposed between the outer facing layer and the inner facing layer of the bottom surface of the balloon member;
• a first plurality of electrodes patterned onto the top flexible framework;
• a second plurality of electrodes patterned onto the bottom flexible framework, wherein the first plurality of electrodes are aligned with the second plurality of electrodes, wherein one or more electrodes of the first plurality of electrodes and/or the second plurality of electrodes are configured to deliver pulsed field ablation energy to a tissue;
• a plurality of conductive traces disposed on each of the flexible frameworks, each of the plurality of conductive traces electrically coupled with a respective one of the first plurality of electrodes and the second plurality of electrodes;
• and
• a flexible structural element disposed within the interior cavity.