Smart meters run on two frequencies. The frequency communicating to the electric meter is 900 MHz (megahertz). If the premise also has a gas meter, the frequency from the electric meter to the gas meter is 2.4 GHz (gigahertz).
The electric meter frequency is similar to a cell phone and the gas meter frequency is similar to a computer router. Neither device will interfere with any wireless devices in the home and it is highly unlikely that the relatively weak fields produced the meter would interfere with the operation of a medical device.