Abstract: A medical electrical pulse generator having a switchable connector assembly. The connector assembly is provided with connector bores, each intended to receive a medical electrical lead or a sealing plug, if no lead is provided. Electrical connectors located within the bores are arranged such that interconnection of the pulse generator circuitry within the device and electrodes on the leads and/or housing of the device can be altered by means of connector pins located on the electrical leads or the sealing plugs, which may be employed to interconnect electrical connectors within a connector bore.

Abstract: A pacemaker system adapted to delivery pacing pulses in the presence of tachycardia or bradycardia. The pacing pulses are delivered via large surface area electrodes of the type normally used to accomplish defibrillation or cardioversion. Delivery of pacing pulses using the large surface area electrodes results in a more simultaneous depolarization of the heart tissue and is believed beneficial to improve hemodynamic efficiency of paced heart beats and in terminating detected tachyarrhythmias.