Mains interference in ECG recording

Abstract

Despite the increasing sophistication of ECG monitoring and recording equipment, the problem of mains interference and the techniques used to overcome it remain of fundamental importance.

This paper presents simplified models of the instrumentation systems most commonly encountered in a hospital environment, concentrating on the ubiquitous isolated amplifier. Empirical values are given for the various parameters, and simple equations are developed to estimate the interference levels in practical situations.

Key Words:

• a.c. mains
• Interference
• ecg