Twelve-Lead EKG on an Amputee With a Tremor
You are asked to obtain a 12-lead EKG on Mr. Brennan, age 68, before his preoperative visit. He has a left below-elbow amputation and a noticeable resting tremor in both arms. He is alert, oriented, and consents. He reports no chest pain but says he "gets winded" walking to the bathroom. The room is cool, and he is wearing a long-sleeved shirt. The provider's note says "rule out arrhythmia; compare to prior." You have one set of electrodes and limited time before the next patient.
1. How do you place limb leads on a patient with a left below-elbow amputation, and why does placement matter?
Read the worked answer
Place leads on the limb, not the missing segment. Standard limb lead positions are on the limbs; when a distal limb is absent, place the electrode on the most distal available tissue of that limb - for a below-elbow amputation, the upper arm/shoulder region on the left - and keep the placement consistent with how prior and future EKGs will be done so tracings are comparable.
Why it matters:
- Limb leads are not interchangeable; swapping left and right arm leads produces recognizable but misleading patterns (e.g., inverted P and QRS in lead I) that can mimic pathology.
- Inconsistent placement between this EKG and the prior study undermines the "compare to prior" request.
- Document the modification on the tracing so the interpreting provider knows the limb lead was not in the standard location.
Also: expose the chest and limbs adequately (the long sleeves must come off or be repositioned) so electrodes adhere to skin, not fabric, and prep the skin to reduce artifact.
2. The tremor is producing a wandering, noisy baseline. What do you do, and what must you not do?
Read the worked answer
Reduce artifact without falsifying the tracing.
- Warm and prepare the skin: a cool room plus poor adhesion increases artifact; dry, abrade lightly, and ensure good contact.
- Position for comfort: support the arms on pillows or the bed so muscles relax; a supported limb tremors less than a hanging one.
- Ask the patient to relax and stay still, and consider having him exhale and hold briefly during acquisition if that helps and is safe.
- Check the machine: verify filter settings and that the paper/display is not the source of the noise.
- Repeat the tracing if the baseline remains unreadable, and note on the record that tremor artifact was present.
Do not:
- Do not adjust filter settings to disguise a real arrhythmia or "clean up" the tracing in a way that hides genuine waveform information.
- Do not fabricate or reinterpret a rhythm you cannot actually see; if the tracing is uninterpretable, say so and let the provider decide about repeating or using another modality.
Judgment point: an unreadable but honestly labeled EKG is safer than a tidy-looking one that has been filtered into a false sense of security.