An implantable medical device for use in a patient management system is described, including a sensor capable of measuring a body characteristic and generating a data signal describing the measurement, and a processor configured to analyze the data signal and identify one or more significant events that warrant attention for the well-being of a patient. The implantable medical device further includes a first non-rechargeable battery configured to power at least the sensor and the processor. In addition, a first communications unit is configured to be powered by the first non-rechargeable battery and includes a wireless transmitter capable of establishing a first communications link with a host computer using an external local receiver, when said first wireless transmitter is within a short-range telemetry communication range of said local receiver, to deliver notification of the significant events to the host computer. The implantable medical device also includes a second rechargeable battery and a second communications unit powered by the second rechargeable battery. The second communications unit is capable of establishing a second communications link with said host computer over a pervasive wireless communications network, such as a cell phone network, to deliver notification of the significant events to the host computer.