EKG/ECG Lead Placement and Artifacts Flashcards
6 cards from real NCMA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 EKG/ECG Lead Placement and Artifacts flashcards as text
Where is the V4 precordial electrode placed for a standard 12-lead EKG?
Answer: Fifth intercostal space, left midclavicular line
Proper lead placement is critical for an accurate EKG. The V4 electrode is placed in the fifth intercostal space at the midclavicular line. This placement follows the placement of V1, V2, and V3, and provides a specific view of the heart's electrical activity.
An EKG tracing shows a fuzzy, irregular baseline with erratic spikes. This is most likely caused by which type of artifact?
Answer: Somatic Tremor
Somatic tremor is an artifact caused by muscle movement, such as patient shivering, talking, or involuntary tremors. It appears as a fuzzy, erratic baseline on the EKG tracing. Ensuring the patient is warm, comfortable, and still can help minimize this type of artifact.
On an EKG, what does the P wave represent?
Answer: Atrial depolarization
The P wave is the first positive deflection on the EKG and represents atrial depolarization. This is the electrical activation of the atria, which leads to atrial contraction. The QRS complex represents ventricular depolarization, and the T wave represents ventricular repolarization.
A wandering baseline artifact on an EKG is often caused by:
Answer: Poor electrode contact or patient breathing
A wandering baseline is a slow, undulating up-and-down motion of the entire tracing. It is often caused by poor electrode contact with the skin, which can be due to lotions, oils, sweat, or patient movement like deep breathing. Properly preparing the skin and ensuring electrodes are secure can prevent this artifact.
Which limb electrode is considered the ground lead in a standard 12-lead EKG?
Answer: Right Leg (RL)
The right leg (RL) electrode serves as the ground lead in an EKG. Its purpose is to minimize electrical interference from outside sources, which helps to produce a clearer tracing. While it is placed on the patient, it does not contribute to any of the specific EKG leads but is essential for the overall quality of the recording.
AC interference on an EKG tracing appears as:
Answer: A series of small, uniform spikes creating a thick, fuzzy line
AC (alternating current) interference is caused by electrical interference from nearby power sources, such as lights, power cords, and other medical equipment. It appears as a uniform, thick, and shaky line, typically with small, rapid spikes at a frequency of 60 Hz in the United States. Ensuring the patient bed is away from walls and unplugging non-essential equipment can resolve this.