Special Patient Considerations in EKG Acquisition

Why Special Considerations Matter

A 12-lead EKG is only as reliable as the acquisition technique behind it. Standard electrode placement assumes an average adult body with intact skin, no implanted hardware, and a normally positioned heart. In real clinical settings, patients frequently present with conditions that require you to adapt your technique. Failing to adapt produces artifact, misplaced leads, or — in the worst case — a tracing that leads to a misdiagnosis. Your job as an EKG technician is to recognize these situations, make the correct adjustment, and document what you did. You do not interpret the tracing or change the clinical plan; that is the provider's role.

Patients with Mastectomy Scars or Chest Wall Changes

After a mastectomy, breast tissue is absent on one or both sides. Scar tissue may be present. This changes the landmark anatomy you normally use to position precordial electrodes.

Key adaptation: Locate bony landmarks — the sternum, clavicle, and intercostal spaces — by palpation rather than relying on tissue landmarks. Scar tissue has higher electrical impedance than normal skin, which increases the chance of artifact. Gently clean and dry the scar area; if the skin surface is irregular, press the electrode firmly to maximize contact. Never skip a precordial position because tissue is absent. Place each electrode at the correct anatomical intercostal space and sternal or mid-clavicular reference line, regardless of what the overlying surface looks like. Document the mastectomy and any placement variation in the patient record.

Patients with Obesity or Large Body Habitus

Excess adipose tissue shifts soft-tissue landmarks and increases skin-to-electrode distance, which can reduce signal quality and introduce low-frequency baseline artifact.

Key adaptation: Palpate intercostal spaces carefully — they may be harder to locate. For limb leads on very large extremities, place limb electrodes on the upper arm and upper thigh (or the proximal fleshy area) rather than the wrist and ankle if standard placement cannot maintain stable contact. Do not place limb electrodes on the torso to avoid axis errors unless specifically directed by facility protocol. For the precordials, lift or reposition tissue as needed to expose the chest wall, and ask for a same-gender chaperone if appropriate. Use a larger or high-tack electrode if standard electrodes will not adhere. Document any placement modifications.

Patients with Implanted Cardiac Devices

Pacemakers, implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices have a generator — a small metal box — usually implanted subcutaneously below the left or right clavicle.

Key adaptation: Do not place an electrode directly over the generator. Placing an electrode on top of the generator will not injure the patient, but it produces poor contact and artifact because of the rigid surface. Shift the affected electrode slightly — typically the V1 or a limb lead — to the nearest adjacent skin area that has adequate subcutaneous tissue and is free of the device. Note the device location and your adjustment in the documentation. The EKG tracing of a paced patient will look different from a non-paced patient; pacemaker spikes may be visible. Do not be alarmed by this appearance. Your role is to acquire the tracing and report it; the provider evaluates the device function.

Safety point: Never attempt to reprogram, magnet-test, or otherwise interact with an implanted device. That is outside your scope of practice.

Patients with Suspected or Known Dextrocardia

Dextrocardia is a congenital condition in which the heart is a mirror image of its normal position, sitting on the right side of the chest. On a standard 12-lead tracing, dextrocardia produces a characteristic pattern: the P wave is inverted in lead I, there is progressive R-wave decrease across the precordial leads (rather than the normal R-wave progression), and lead I looks like an inverted version of what you would expect.

Key adaptation: When dextrocardia is known or suspected, perform a right-sided EKG. This means placing the precordial electrodes as mirror images of their standard positions — V1 and V2 remain at the sternal borders (they are already near the midline), but V3R through V6R are placed on the right side of the chest in mirror-image positions. Some facilities also reverse limb lead placement (right arm and left arm electrodes swapped) to confirm the pattern. Always label the tracing clearly as "Right-Sided EKG" or with the lead designations (V3R, V4R, V5R, V6R) so the provider interprets it correctly. Never submit an unlabeled right-sided tracing as a standard 12-lead.

Skin Integrity Concerns Across All Patients

Diabetic patients, elderly patients, and those on long-term corticosteroids often have fragile skin. When removing electrodes, peel slowly and support the skin with your other hand to prevent tearing. Do not use aggressive skin-prep abrasives on fragile or broken skin. If a patient has open wounds, rashes, or burns at a standard electrode site, place the electrode at the nearest clean, intact site and document the deviation.

Scope of Practice and Documentation

In all of these situations, your scope of practice as an EKG technician remains constant: acquire the tracing, adapt technique to get the best quality signal, document your adaptations, and report any unusual findings or patient concerns to the supervising clinician. You do not diagnose arrhythmias, adjust device settings, or make treatment decisions. If you notice an unexpected finding — such as an unusual rhythm, patient distress, or a device you were not told about — stop, ensure patient safety, and notify the nurse or provider immediately.