Abstract: A triple port and quadruple port header assembly of an implantable tissue stimulator, such as a pacemaker, defibrillator, or nerve stimulator, wherein three or more sensing and/or pacing leads may be coupled thereto. Ports of the header assembly receive the terminal end of corresponding leads, wherein each port has two terminal blocks positioned therein which are adapted for coupling a pin and/or ring of the terminal end of the corresponding lead. Feedthrough wires electrically couple the terminal blocks to the electronic circuit of the implantable tissue stimulator, and jumper wires electrically couple the terminal blocks of at least two ports, thereby electrically coupling the corresponding pins and/or rings of at least two leads contained therein.