Resting ECG Procedures Flashcards

A technician acquires a 12-lead ECG and notices the baseline is drifting up and down in a slow, sinusoidal pattern. What is the most likely cause?

Answer: Respiratory motion artifact (breathing-related baseline wander) from electrode movement during respiration

Slow, sinusoidal baseline wander that follows the respiratory cycle is caused by respiratory motion — as the thorax expands and contracts, electrodes shift slightly on the skin, causing a slow, wave-like baseline drift.

For a 12-lead ECG, where are the limb electrodes placed to meet the standard AHA guidelines when the patient has a below-knee amputation on the right leg?

Answer: Place the right leg electrode on the right thigh or the most distal right limb stump

When a standard electrode position is unavailable due to amputation, the electrode should be placed on the most distal available part of that limb (the stump or thigh). This is noted on the ECG for the interpreting physician.

What does the standard acquisition time for a 12-lead resting ECG represent — how many seconds of each lead are typically recorded in a standard 12-channel simultaneous acquisition?

Answer: Typically 10 seconds of simultaneous recording across all 12 leads, providing approximately 2.5 seconds per grouping in some formats

A standard 12-lead ECG records all 12 leads simultaneously for approximately 10 seconds, providing enough cardiac cycles for reliable rhythm analysis and interval measurement at 25 mm/second paper speed.

Why should limb electrodes be placed on the distal limbs (wrists and ankles) rather than the proximal limbs during a resting ECG?

Answer: Distal placement reduces muscle artifact from limb movement and provides the correct geometric reference for Einthoven's triangle, consistent with the standard derivation of limb leads

Distal limb placement minimizes artifact from proximal muscle groups and maintains the standardized geometric relationship that the limb lead derivations (Einthoven's equations) assume. Placing electrodes proximally alters lead axes slightly.

Which of the following statements best describes the role of the right leg (RL) electrode in a standard 12-lead ECG?

Answer: The RL electrode serves as an electrical reference/ground that drives the common-mode rejection system, improving signal quality, and does not contribute to any of the 12 standard leads

The right leg electrode serves as a driven ground reference that helps the ECG amplifier reject common-mode interference (like AC noise), improving signal quality. It does not directly contribute to any of the 12 standard ECG leads.

What action should a CCT technician take if they observe that the ECG technician's copy of the tracing shows a technically poor-quality recording due to significant artifact?

Answer: Repeat the ECG after addressing the artifact source before sending the tracing for physician interpretation

A technically poor-quality ECG should be repeated after correcting the artifact source before submission for clinical interpretation, because artifact can mimic or obscure real findings, potentially leading to diagnostic error.