Chapter 39: Dysrhythmias Flashcards
intro to ECG
abnormal heart rhythms
dysrhythmias
T/F
Dysrhythmias can directly decrease cardiac output (CO) by changing stroke volume and heart rate.
true
Name the parts of the autonomic nervous system (ANS) that affect the heart.
- vagus nerve fibers of the parasympathetic nervous system (PNS)
- nerve fibers of the sympathetic nervous system (SNS)
Stimulation of the __________ nerve slows firing of the sinoatrial (SA) node and slows impulse conduction of the AV node, this __________ heart rate.
vagus ; decreases
Stimulation of the __________ nerves increases sinoatrial (SA) node firing, AV node impulse conduction, and cardiac contractility. This __________ heart rate.
sympathetic ; increases
a graphic tracing of the electrical impulses in the heart
electrocardiogram (ECG)
What do the waveforms on the electrocardiogram (ECG) represent?
the electrical activity of depolarization and repolarization produced by the movement of ions across the membranes of heart cells
T/F
The membrane of a heart cell is semipermeable.
true
the inside of the cell is positively charged compared with the outside
depolarization
a slower movement of ions across the membrane restores the cell to the polarized state
repolarization
T/F
A 6-lead electrocardiogram (ECG) view of the heart is helpful in assessing dysrhythmias.
false; 12-lead
ability to initiate an impulse spontaneously and continuously
a. contractility
b. automaticity
c. excitability
d. conductivity
b. automaticity
ability to be electrically stimulated
a. contractility
b. automaticity
c. excitability
d. conductivity
c. excitability
ability to transmit an impulse along a membrane in an orderly manner
a. contractility
b. automaticity
c. excitability
d. conductivity
d. conductivity
ability to respond mechanically to an impulse
a. contractility
b. automaticity
c. excitability
d. conductivity
a. contractility
What are the most common leads in an electrocardiogram (ECG)?
leads II and V
What is the most accurate way to calculate the heart rate from an electrocardiogram (ECG)?
count the number of QRS complexes in 1 minute
a distortion of the baseline and waveforms seen on the electrocardiogram (ECG)
artifact
Match the correct wavelength to the description.
represents time for the passage of the electrical impulse through the atrium causing atrial depolarization (contraction, should be upright
a. P wave
b. PR interval
c. QRS complex
d. QRS interval
a. P wave
Match the correct wavelength to the description.
- measured from beginning of P wave to beginning of QRS complex
- represents time taken for impulse to spread through the atria, AV node and bundle of His, bundle branches, and Purkinje fibers to a point immediately before ventricular contraction
a. ST segment
b. PR interval
c. T wave
d. P wave
b. PR interval
Match the correct wavelength to the description.
Q, R, and S wave
a. QRS interval
b. QT interval
c. ST segment
d. QRS complex
d. QRS complex
Q, R, or S wave?
first negative (downward) deflection after the P wave, short and narrow, not present in several leads
Q wave
Q, R, or S wave?
first positive (upward) deflection in the QRS complex
R wave
Q, R, or S wave?
first negative (downward) deflection after the R wave
S wave
Match the correct wavelength to the description.
- measured from beginning to end of QRS complex
- represents time taken for depolarization (contraction) of both ventricles (systole)
a. QRS interval
b. ST segment
c. P wave
d. QRS complex
a. QRS interval
Match the correct wavelength to the description.
- measured from the S wave of the QRS complex to the beginning of the T wave
- represents the time between ventricular depolarization and repolarization (diastole)
- should be flat
a. QT interval
b. Q wave
c. ST segment
d. R wave
c. ST segment
Match the correct wavelength to the description.
- represents time for ventricular repolarization
- should be upright
a. Q wave
b. R wave
c. S wave
d. T wave
d. T wave
Match the correct wavelength to the description.
- measured from beginning of QRS complex to end of T wave
- represents time taken for entire electrical depolarization and repolarization of the ventricles
a. QRS complex
b. QT interval
c. QRS interval
d. ST segment
b. QT interval
T/F
Adult men have slightly longer QT intervals than women.
false; women have longer QT intervals
the observation of a patient’s heart rate and rhythm at a side distant from the patient
telemetry monitoring
T/F
Dysrhythmias result from disorders of impulse formation, impulse conduction, or both.
true
natural pacemaker of the heart
sinoatrial (SA) node
the recovery period after stimulation
a. refractory phase
b. absolute refractory phase
c. relative refractory period
d. full excitability
a. refractory phase
occurs when excitability is zero, and the heart cannot be stimulated
a. refractory phase
b. absolute refractory phase
c. relative refractory period
d. full excitability
b. absolute refractory phase
occurs slightly later in the cycle, and excitability is more likely
a. refractory phase
b. absolute refractory phase
c. relative refractory period
d. full excitability
c. relative refractory period
heart is completely recovered
a. refractory phase
b. absolute refractory phase
c. relative refractory period
d. full excitability
d. full excitability
What would the nurse measure to determine whether there is a delay in electrical impulse conduction through the patient‘s ventricles?
a. P wave
b. Q wave
c. PR interval
d. QRS complex
d. QRS complex
The nurse needs to measure the heart rate for a patient with an irregular heart rhythm. Which method will be accurate?
a. Count the number of large squares in the R-R interval and divide by 300.
b. Print a 1-minute electrocardiogram (ECG) strip and count the number of QRS complexes.
c. Use the 3-second markers to count the number of QRS complexes in 6 seconds and multiply by 10.
d. Calculate the number of small squares between one QRS complex and the next and divide into 1500.
b. Print a 1-minute electrocardiogram (ECG) strip and count the number of QRS complexes.
Which action by a registered nurse (RN) who is orienting to the telemetry unit indicates a good understanding of the treatment of heart dysrhythmias?
a. Prepares defibrillator settings at 360 joules for a patient whose monitor shows asystole.
b. Injects IV adenosine over 2 seconds for a patient with supraventricular tachycardia.
c. Turns the synchronizer switch to the “on” position before defibrillating a patient with ventricular fibrillation.
d. Gives the prescribed dose of diltiazem (Cardizem) to a patient with new-onset type II second-degree AV block.
b. Injects IV adenosine over 2 seconds for a patient with supraventricular tachycardia.
