Chapter 34: Electrocardiography
A patient is being continuously monitored on the telemetry unit and has had stable rhythm, as noted on the electrocardiogram (ECG) strip. The patient asks when his monitor can be discontinued. What is an appropriate response by the nurse?
"Monitoring can usually be suspended for showering and transport to other units."
A patient is recovering from a myocardial infarction but has developed a dysrhythmia. The patient asks the nurse what caused the change in rhythm. Which explanation by the nurse is accurate?
"Other cardiac cells in addition to the SA node create electrical impulses, causing a dysrhythmia."
Which is an expected finding for a normal PR interval?
0.16 seconds
When determining irregular heart rate on an electrocardiogram (ECG) rhythm strip, which method is used for best accuracy?
6-second strip method
A patient has an abnormal PR segment on the electrocardiogram (ECG). What part of the heart does the nurse attribute to the abnormal wave?
AV node
Which statements are true regarding artifacts seen on the monitor or rhythm strip? Select all that apply.
An artifact may look like a fuzzy baseline. An artifact may mimic a lethal dysrhythmia. An artifact can be caused by patient movement or loose electrodes.
What is the ability of the cardiac cells to generate an electrical impulse spontaneously and repetitively called?
Automaticity
How does the nurse establish that an impulse from one focus is responsible for both atrial and ventricular depolarization?
Check that one P wave occurs before each QRS complex.
A systematic approach is needed to analyze the electrocardiogram (ECG) strip using an eight-step method. Place these steps in the correct order.
Determine the heart rate Determine the heart rhythm Analyze the P waves Measure the PR interval
In which location would the nurse place lead II for a positive deflection electrocardiogram (ECG)?
Fourth intercostal space, left of the sternal border
The nurse is preparing to perform a 12-lead electrocardiogram (ECG) on a patient. Where does the nurse place the first V-lead (precordial lead)?
Fourth intercostal space, right sternal border
What represents no electrical current flow in the heart on the electrocardiogram (ECG)?
Isoelectric line
Which is a characteristic of the ST segment?
It occurs from the J point to the beginning of the T wave.
Which criteria does the normal sinus rhythm meet? Select all that apply.
It originates from the SA node. The QRS duration is 0.04-0.10 seconds.
What is important for the nurse to know about the P wave in sinus rhythm when examining a rhythm strip?
It precedes the QRS complex.
In addition to the 12-lead electrocardiogram (ECG), other lead systems include the 18-lead ECG. What is the advantage of the 18-lead ECG?
It provides more information about the right side of the heart.
Which steps are involved in the electrocardiographic rhythm analysis of P waves? Select all that apply.
Looking for the presence of P waves Analyzing the similarity in appearance of P waves Assessing the consistent occurrence of one P wave for each QRS complex
The nurse observes abnormal T waves in the electrocardiogram of a patient with dysrhythmia. What is the possible reason for the patient's dysrhythmia?
Myocardial infarction
What complexes make up a normal electrocardiogram (ECG)? Select all that apply.
P T QRS
Which complex makes up a normal electrocardiogram (ECG)?
QRS
An adult patient is scheduled for a 12-lead electrocardiogram (ECG) to rule out a dysrhythmia. Four of the leads are placed on the extremities. Which extremity is used for the ground electrode?
Right leg
Contractility, or the mechanical activity of the heart, occurs in a specific order to push the blood forward. What is the order of conduction that best identifies the contractility of the heart?
SA node, AV node, bundle of His, left bundle branch
What component of a normal electrocardiogram represents early ventricular repolarization?
ST segment
A patient's rhythm strip shows a heart rate of 116 beats/min, one P wave occurring before each QRS complex, a PR interval measuring 0.16 second, and a QRS complex measuring 0.08 second. How does the nurse interpret this rhythm strip?
Sinus tachycardia
The nurse wants to determine the patient's average heart rate by observing the electrocardiogram (ECG) strip. She counts the number of QRS complexes documented within 6 seconds and multiplies that number by 10. What is this method called?
The 6-second method
The nurse evaluates the placement of the electrodes to ensure clarity of monitoring. What ensures appropriate electrode preparation and placement? Select all that apply.
The electrode gel is moist No lotion is present on the patient's skin The nurse selected the leads and checked placement Chest hair is shaved or clipped where electrodes will be placed
Who is responsible for determining when continuous electrocardiogram (ECG) monitoring can be suspended, such as during showering?
The health care provider
The professional nurse is supervising a nursing student performing a 12-lead electrocardiogram (ECG). Under which circumstance does the nurse correct the student?
The patient is instructed to breathe deeply through the mouth.
The nurse is reviewing the electrocardiography (ECG) strip after it is printed. How does the nurse interpret the data of the strip?
Time is measured on the horizontal axis.
