A catheterization system, comprising: a flexible catheter adapted for insertion into a heart of a living subject, having a distal portion and a lumen for passing an electrolyte-containing fluid therethrough to exit the catheter at the distal portion, the lumen connectable to an irrigation pump to form a fluid communication therewith; a fluid reservoir connected to the irrigation pump for supplying electrolyte-containing fluid to the catheter; electrocardiogram circuitry connectable to the subject for monitoring electrical activity in the heart, the electrocardiogram circuitry including a patient interface unit having an analog input and an isolated ground; characterised by: a drip chamber connected between the fluid reservoir and the irrigation pump for receiving the electrolyte containing fluid therein; a connector connected between the drip chamber and the irrigation pump, the connector comprising: an outer metal shell; a lumen filled with an electrically conductive net or sponge and configured to allow the flow through the lumen of the electrolyte containing fluid; and an electrical connector on the metal shell; and an electrically conductive cable connected between the electrical connector and the isolated ground of the patient interface unit; wherein the electrical connector on the metal shell provides electrical continuity between electrolyte containing fluid flowing through the lumen, the electrically conductive net or sponge and the electrically conductive cable. a flexible catheter adapted for insertion into a heart of a living subject, having a distal portion and a lumen for passing an electrolyte-containing fluid therethrough to exit the catheter at the distal portion, the lumen connectable to an irrigation pump to form a fluid communication therewith; a fluid reservoir connected to the irrigation pump for supplying electrolyte-containing fluid to the catheter; electrocardiogram circuitry connectable to the subject for monitoring electrical activity in the heart, the electrocardiogram circuitry including a patient interface unit having an analog input and an isolated ground; characterised by: a drip chamber connected between the fluid reservoir and the irrigation pump for receiving the electrolyte containing fluid therein; a connector connected between the drip chamber and the irrigation pump, the connector comprising: an outer metal shell; a lumen filled with an electrically conductive net or sponge and configured to allow the flow through the lumen of the electrolyte containing fluid; and an electrical connector on the metal shell; and an electrically conductive cable connected between the electrical connector and the isolated ground of the patient interface unit; wherein the electrical connector on the metal shell provides electrical continuity between electrolyte containing fluid flowing through the lumen, the electrically conductive net or sponge and the electrically conductive cable. a drip chamber connected between the fluid reservoir and the irrigation pump for receiving the electrolyte containing fluid therein; a connector connected between the drip chamber and the irrigation pump, the connector comprising: an outer metal shell; a lumen filled with an electrically conductive net or sponge and configured to allow the flow through the lumen of the electrolyte containing fluid; and an electrical connector on the metal shell; and an outer metal shell; a lumen filled with an electrically conductive net or sponge and configured to allow the flow through the lumen of the electrolyte containing fluid; and an electrical connector on the metal shell; and an electrically conductive cable connected between the electrical connector and the isolated ground of the patient interface unit; wherein the electrical connector on the metal shell provides electrical continuity between electrolyte containing fluid flowing through the lumen, the electrically conductive net or sponge and the electrically conductive cable.