An Electromagnetic Interference site survey (EMI site survey) is an independent assessment of potential EMI risks. These risks might interfere with an implantable electrical device such as a pacemaker or defibrillator. 

An EMI site survey provides the electromagnetic environment of a facility. Essentially, a site survey determines the electromagnetic waves and radio frequency (RF) that are active in a location.

The world is becoming more electronically-dependent on a daily basis. This poses increasing potential risks for patients with implantable electrical devices such as pacemakers and defibrillators. Patients must be cognizant of their surroundings at all times. The response of a pacemaker or defibrillator or other implantable electrical device to interference from other devices depends on a number of variables including, the polarity of the device, the amount of shielding on the device, the strength and location of the signal and the duration of the exposure to the interference.