A circuit card assembly (CCA) comprises a printed circuit board (PCB) having first and second opposing major faces with a first pair of elongated edges extending therebetween. Heat management layers are disposed within the CCA and/or PCB, which extend to said edges, and a thermally conductive bar is engaged in a slot provided in each of the elongated edges. Each conductive bar extends over at least the thickness of the PCB, one face preferably being flush with one of the major faces of the PCB and is thermally connected to the heat management layer(s) by thermal connecting means so as to conduct heat from the or each heat management layer to said bar.