Various configurations of systems that employ leadless electrodes to
provide pacing therapy are provided. In one example, a system that
provides multiple sites for pacing of myocardium of a heart includes
wireless pacing electrodes that are implantable at sites proximate the
myocardium using a percutaneous, transluminal, catheter delivery system.
Each of the electrodes contains a source of electrical energy for pacing
the myocardium and is adapted to receive electromagnetic energy from a
source outside the myocardium. The system also includes a source adapted
for placement outside the myocardium and that uses locally measured
electrocardiograms to synchronize pacing of the heart by sending
electromagnetic commands to the electrodes to pace the myocardium
surrounding the electrodes. Also disclosed is various configurations of
such systems, wireless electrode assemblies, and delivery catheters for
delivering and implanting the electrode assemblies.