An apparatus includes a cardioversion or defibrillation therapy energy source coupled to a bridge circuit. The bridge circuit includes a first switch for connection to a first implantable electrode, a second switch for connection to a second implantable electrode, a third switch coupled for connection to the first implantable electrode, and a fourth switch coupled for connection to the second implantable electrode. The first and second switches are formed on a shared first IC, the third and fourth switches are formed on a shared second IC, and the second IC is stacked substantially superjacent to the first IC such that a cathode of the first switch is coupled to an anode of the third switch and a cathode of the second switch is coupled to an anode of the fourth switch.