Equipment and Quality Control
Understand the equipment used in cardiac monitoring and testing and how to keep it accurate. Know ECG electrodes, lead wires, cables, monitors, and the importance of proper skin preparation and electrode placement to reduce artifact. Recognize common artifacts: baseline wander from movement or respiration, muscle tremor, and 60-cycle interference from electrical sources.
Quality control includes daily checks, calibration where applicable, verifying battery and power status, and confirming that cables and connectors are intact. Understand that poor electrode contact produces false alarms and misleading rhythm interpretation. Know basic troubleshooting: reposition or replace electrodes, prepare skin, secure cables, and reduce patient movement.
Traps: interpreting artifact as a true arrhythmia; ignoring a low battery or disconnected lead alarm; placing electrodes over bone or hair without preparing skin; and assuming a monitor is accurate without checking leads and connections. Another trap is failing to recognize that a wandering baseline may be caused by respiration or loose electrodes rather than a cardiac event.
Rule of thumb: "Before you believe the rhythm, believe the setup." If the tracing looks impossible or changes with movement, check electrodes, cables, and connections first.
Worked example: a monitor shows a thick, fuzzy baseline with no clear QRS. This is likely muscle tremor or interference, not a lethal rhythm. Check electrode placement and skin preparation, secure the cables, and reassess before escalating as a rhythm change - while still confirming the patient's clinical status.