Burdick ELI 280 Lead Reading Artifact Repair Case Study

A healthcare facility reported that a Burdick ELI 280 ECG machine was failing to read leads properly, showing intermittent blackouts, and producing inaccurate traces. Reliable electrocardiograph acquisition is critical for timely diagnostic evaluation and patient safety. A PBES technician was dispatched to evaluate the device and determine the source of signal loss and trace distortion.

Technician investigation

The technician inspected the patient cable assembly, verifying that all individual leads were fully seated into the main trunk cable and that the patient cable was firmly connected to the acquisition module. The machine was connected to an ECG simulator, where it tested and validated properly. However, when connected to a patient, significant signal artifact was observed, matching the reported clinical complaint.

Root cause

Suspected: Lead contamination and improper filter configuration contributing to baseline noise and artifact An isolated root cause was not definitively documented in the service report. While simulator testing showed proper hardware function, trace degradation occurred specifically under live patient acquisition.

• Patient trunk cable disconnection
• Simulator-level hardware failure on the acquisition interface

Resolution

The technician confirmed physical seating of all patient leads and the main cable interface. Internal filtering was adjusted by setting the AC filter to 60Hz and configuring the frequency filter to 150Hz to minimize ambient electrical interference. The technician cleaned the Left Leg (LL) lead contact to eliminate localized high-impedance contamination. Additionally, the technician noted that the unit required a battery replacement, though no replacement part installation was documented on this work order.

Verification

• Simulator testing with an ECG tester
• Lead continuity and cable seating checks

Validating an ECG on a calibrated patient simulator ensures internal acquisition circuitry and software processing function correctly. Follow-up live acquisition checks verify that filtering and physical lead integrity sustain clean waveforms in actual clinical environments.

Technician insight

Technician Insight: It is common for an ECG device to pass bench testing on a simulator yet produce artifact on a live patient. Simulators deliver clean, high-amplitude, low-impedance signals that bypass skin resistance, motion, and ambient AC noise. Checking physical lead cleanliness and verifying that AC notch filters match local power line frequency (60Hz) are critical baseline troubleshooting steps before suspecting mainboard failure.

What can cause this issue?

• High electrode-to-skin impedance or contaminated lead wire snaps
• Incorrect AC notch filter settings allowing 60Hz power line interference
• Broken or fatigued conductors within the patient cable assembly
• Failing internal battery unable to maintain stable DC bus voltage under load
• Poor grounding or environmental electromagnetic interference

In this specific service event, the machine passed simulator testing, but displayed artifact on patient hookup. The technician adjusted the AC filter to 60Hz, set the low-pass filter to 150Hz, cleaned the Left Leg lead contact, and noted a battery replacement requirement.

FAQ

Why did the Burdick ELI 280 test fine on a simulator but fail on a patient?

An ECG simulator provides an ideal, noise-free signal with consistent impedance. In real-world patient acquisition, physiological factors, skin prep, lead contamination, and ambient electrical interference can expose filtering and lead contact deficiencies that a simulator will not trigger.

What is the purpose of changing the AC filter to 60Hz on an ECG?

In North America, standard mains electricity operates at 60Hz. Setting the AC filter to 60Hz specifically targets and suppresses alternating current hum induced by surrounding power lines and electrical equipment.

Why was the Left Leg lead cleaned during troubleshooting?

Debris, dried gel, or oxidation on a lead snap increases electrical resistance at the electrode junction. The Left Leg lead is a reference lead in standard Einthoven limb lead calculations, so poor contact on it can distort multiple ECG vectors.

Was a new battery installed during this call?

The service report notes that the machine required a battery replacement, but no replacement part installation was documented as completed during this specific visit.