Abstract: The intraventricular multielectrode cardiac mapping probe comprises a catheter having an open proximal end and an open distal end and four elongate wire assemblies received in the catheter and having a distal end portion, and a proximal end portion extending from the catheter proximal open end. Each wire assembly comprises a tubing, six insulated wire conductors received in the tubing, and a central core wire which is stiff but yet flexible and which is received in the tubing and extends substantially the length thereof. A proximal connector is mounted on each tubing. The distal end portion of each wire assembly has six spaced apart sleeve electrodes thereon connected to respective ones of the wire conductors.