An irrigated high density electrode catheter, comprising a catheter shaft (107; 134; 154; 389; 495; 702; 780) including a proximal end and a distal end, the catheter shaft defining a catheter shaft longitudinal axis, a flexible tip portion (110; 122; 156; 202; 228; 248; 282; 322; 362; 491) located adjacent to the distal end of the catheter shaft and comprising a plurality of microelectrodes (102, 124), an irrigated coupler (324; 364; 462; 560; 720; 760; 802) disposed on the distal end of the catheter shaft and configured to discharge fluid over the flexible tip portion; a six degree of freedom sensor assembly; and a connective stem having a longitudinal axis and (326; 366; 458) comprising a top connective stem portion (332; 380; 464; 640) and a bottom connective stem portion (334; 378; 466; 610), wherein the top connective stem portion and the bottom connective stem portion are configured to be assembled and positioned on opposite sides of the longitudinal axis of the stem and wherein the connective stem portions house a proximal end portion of the flexible tip portion, wherein the connective stem is configured to be inserted into the distal end of the catheter shaft (107; 134; 154; 389; 495; 702; 780) and connects the proximal end portion of the flexible tip portion to the catheter shaft, wherein the connective stem (326; 366; 458) includes the six degree of freedom sensor assembly, and wherein the connective stem and the irrigated coupler are configured to accommodate coupling of the irrigated coupler to the connective stem after insertion of the connective stem into the distal end of the catheter shaft. a catheter shaft (107; 134; 154; 389; 495; 702; 780) including a proximal end and a distal end, the catheter shaft defining a catheter shaft longitudinal axis, a flexible tip portion (110; 122; 156; 202; 228; 248; 282; 322; 362; 491) located adjacent to the distal end of the catheter shaft and comprising a plurality of microelectrodes (102, 124), an irrigated coupler (324; 364; 462; 560; 720; 760; 802) disposed on the distal end of the catheter shaft and configured to discharge fluid over the flexible tip portion; a six degree of freedom sensor assembly; and a connective stem having a longitudinal axis and (326; 366; 458) comprising a top connective stem portion (332; 380; 464; 640) and a bottom connective stem portion (334; 378; 466; 610), wherein the top connective stem portion and the bottom connective stem portion are configured to be assembled and positioned on opposite sides of the longitudinal axis of the stem and wherein the connective stem portions house a proximal end portion of the flexible tip portion, wherein the connective stem is configured to be inserted into the distal end of the catheter shaft (107; 134; 154; 389; 495; 702; 780) and connects the proximal end portion of the flexible tip portion to the catheter shaft, wherein the connective stem (326; 366; 458) includes the six degree of freedom sensor assembly, and wherein the connective stem and the irrigated coupler are configured to accommodate coupling of the irrigated coupler to the connective stem after insertion of the connective stem into the distal end of the catheter shaft.