Module 12 Exam Material Flashcards
1
Q
Arrhythmias
A
Disorders of formation or conduction (or both) of electrical impulses within heart
2
Q
Arrhythmias can cause disturbances in
A
Can cause disturbances of
Rate
Rhythm
Both rate and rhythm
3
Q
Arrhythmias potentially alter
A
blood flow and cause hemodynamic changes
4
Q
How are arrhythmias diagnosed?
A
by analysis of electrographic waveform
5
Q
Electrical Stimulation
A
Depolarization
6
Q
Mechanical Stimulation
A
Systole
7
Q
Electrical Relaxation
A
Repolarization
8
Q
Mechanical Relaxation
A
Diastole
9
Q
What does the P wave represent?
A
The electrical impulse starting in the SA node and spreading through the atria. Therefore, the P wave represents atrial depolarization
10
Q
What does the QRS complex represent?
A
Represents ventricular depolarization.
Not all QRS complexes have all three waveforms
When a wave is less than 5 mm in height, small letters (q, r, s) are used; when a wave is taller than 5 mm, capital letters (Q, R, S) are used to label the waves.
The QRS complex is normally less than 0.12 seconds in duration.
11
Q
Describe the Q wave
A
The Q wave is normally less than 0.04 seconds in duration and less than 25% of the R-wave amplitude.
12
Q
Describe the R wave
A
The R wave is the first positive deflection after the P wave, and the S wave is the first negative deflection after the R wave
13
Q
What does the T wave represent?
A
Represents ventricular repolarization (when the cells regain a negative charge; also called the resting state)
It follows the QRS complex and is usually the same direction (deflection) as the QRS complex
Atrial repolarization also occurs but is not visible on the ECG because it occurs at the same time as ventricular depolarization (i.e., the QRS).
14
Q
What does the U wave represent?
A
thought to represent repolarization of the Purkinje fibers; although this wave is rare, it sometimes appears in patients with hypokalemia (low potassium levels), hypertension, or heart disease.
If present, the U wave follows the T wave and is usually smaller than the P wave. If larger in amplitude, it may be mistaken for an extra P wave.
15
Q
How is the PR interval measured?
A
measured from the beginning of the P wave to the beginning of the QRS complex and represents the time needed for sinus node stimulation, atrial depolarization, and conduction through the AV node before ventricular depolarization.
16
Q
What does the ST segment represent?
A
represents early ventricular repolarization, lasts from the end of the QRS complex to the beginning of the T wave.
The beginning of the ST segment is usually identified by a change in the thickness or angle of the terminal portion of the QRS complex.
The end of the ST segment may be more difficult to identify because it merges into the T wave. The ST segment is normally isoelectric (see later discussion of TP interval).
It is analyzed to identify whether it is above or below the isoelectric line, which may be, among other signs and symptoms, a sign of cardiac ischemia.
17
Q
What does the QT interval represent?
A
represents the total time for ventricular depolarization and repolarization, is measured from the beginning of the QRS complex to the end of the T wave.
Many medications commonly given in the hospital can cause prolongation of the QT interval (QTc), placing the patient at risk for a lethal ventricular arrhythmia called torsades de pointes.
18
Q
Describe isolelectric line.
A
When no electrical activity is detected, the line on the graph remains flat;
19
Q
Normal Electrical Conduction
A
SA node (sinus node)
AV node
Conduction
Bundle of His
Right and left bundle branches
Purkinje fibers
Depolarization = stimulation = systole
Repolarization = relaxation = diastole
20
Q
What is the RR interval used to determine?
A
ventricular rhythm
21
Q
What is the PP interval used to determine?
A
atrial rhythm
22
Q
Normal Sinus Rhythm
A
Electrical conduction that begins in the SA node generates a sinus rhythm. Normal sinus rhythm occurs when the electrical impulse starts at a regular rate and rhythm in the SA node and travels through the normal conduction pathway.
23
Q
Normal Sinus Rhythm characteristics
A
Ventricular and atrial rate: 60 to 100 bpm in the adult
Ventricular and atrial rhythm: Regular
QRS shape and duration: Usually normal, but may be regularly abnormal
P wave: Normal and consistent shape; always in front of the QRS
PR interval: Consistent interval between 0.12 and 0.20 seconds
P:QRS ratio: 1:1
24
Q
Sinus Bradycardia
A
Sinus bradycardia occurs when the SA node creates an impulse at a slower-than-normal rate.
25
Causes of Sinus Bradycardia
Lower metabolic needs (e.g., sleep, athletic training, hypothyroidism)
Vagal stimulation (e.g., from vomiting, suctioning, severe pain)
Medications (e.g., calcium channel blockers [e.g., nifedipine, amiodarone], beta-blockers [e.g., metoprolol])
Idiopathic sinus node dysfunction
Increased intracranial pressure,
Coronary artery disease, especially myocardial infarction (MI) of the inferior wall.
26
Sinus Bradycardia characteristics
Ventricular and atrial rate: Less than 60 bpm in the adult
Ventricular and atrial rhythm: Regular
QRS shape and duration: Usually normal, but may be regularly abnormal
P wave: Normal and consistent shape; always in front of the QRS
PR interval: Consistent interval between 0.12 and 0.20 seconds
P:QRS ratio: 1:1
27
Sinus Tachycardia
Sinus tachycardia occurs when the sinus node creates an impulse at a faster-than-normal rate
28
Causes of Sinus Tachycardia
Physiologic or psychological stress (e.g., acute blood loss, anemia, shock, hypervolemia, hypovolemia, heart failure, pain, hypermetabolic states, fever, exercise, anxiety)
Medications that stimulate the sympathetic response (e.g., catecholamines, aminophylline, atropine), stimulants (e.g., caffeine, nicotine), and illicit drugs (e.g., amphetamines, cocaine, ecstasy)
Enhanced automaticity of the SA node and/or excessive sympathetic tone with reduced parasympathetic tone that is out of proportion to physiologic demands, a condition called inappropriate sinus tachycardia
Autonomic dysfunction, which results in a type of sinus tachycardia referred to as postural orthostatic tachycardia syndrome (POTS). POTS is characterized by tachycardia without hypotension, and by presyncopal symptoms such as palpitations, lightheadedness, weakness, and blurred vision, which occur with sudden posture changes
29
How is the TP interval measured?
measured from the end of the T wave to the beginning of the next P wave—an isoelectric period
30
How is the PP interval measured?
measured from the beginning of one P wave to the beginning of the next P wave. The PP interval is used to determine atrial rate and rhythm.
31
How is the RR interval measured?
measured from one QRS complex to the next QRS complex. The RR interval is used to determine ventricular rate and rhythm
32
Sinus Tachycardia Characteristics
Ventricular and atrial rate: Greater than 100 bpm in the adult, but usually less than 120 bpm
Ventricular and atrial rhythm: Regular
QRS shape and duration: Usually normal, but may be regularly abnormal
P wave: Normal and consistent shape; always in front of the QRS, but may be buried in the preceding T wave
PR interval: Consistent interval between 0.12 and 0.20 seconds
P:QRS ratio: 1:1
DOES NOT START AND END SUDDENLY
33
Sinus Arrhythmia
Occurs when the sinus node creates an impulse at an irregular rhythm; the rate usually increases with inspiration and decreases with expiratio
34
Causes of sinus arrhythmia
Nonrespiratory causes include heart disease and valvular disease, but these are rare.
35
Sinus Arrhythmia Characteristics
Ventricular and atrial rate: 60 to 100 bpm in the adult
Ventricular and atrial rhythm: Irregular
QRS shape and duration: Usually normal, but may be regularly abnormal
P wave: Normal and consistent shape; always in front of the QRS
PR interval: Consistent interval between 0.12 and 0.20 seconds
P:QRS ratio: 1:1
36
Medical Management of Sinus Arrhythmia
Sinus arrhythmia does not cause any significant hemodynamic effect and therefore is not typically treated.
37
Medical Management of Sinus Bradycardia
If the bradycardia produces signs and symptoms of clinical instability (e.g., acute alteration in mental status, chest discomfort, or hypotension), 0.5 mg of atropine may be given rapidly as an intravenous (IV) bolus and repeated every 3 to 5 minutes until a maximum dosage of 3 mg is given.
38
Medical Management of Sinus Tachycardia
electrical current given in synchrony with the patient’s own QRS complex to stop an arrhythmia is the treatment of choice
39
Premature Atrial Complex
single ECG complex that occurs when an electrical impulse starts in the atrium before the next normal impulse of the sinus node.
40
Causes of Premature Atrial Complex (PAC)
Caffeine
alcohol
nicotine
stretched atrial myocardium (e.g., as in hypervolemia
anxiety
hypokalemia
hypermetabolic states (e.g., with pregnancy), atrial ischemia, injury, or infarction.
41
Medical Management of PAC
If PACs are infrequent; no treatment is necessary. If they are frequent (more than six per minute), this may herald a worsening disease state or the onset of more serious arrhythmias, such as atrial fibrillation. Medical management is directed toward treating the underlying cause (e.g., reduction of caffeine intake, correction of hypokalemia).
42
Risk Factors of Atrial Fibrillation
*Increasing age
*Hypertension
*Diabetes
*Obesity
*Valvular heart disease
*Heart failure
*Obstructive sleep apnea
*Alcohol abuse
*Hyperthyroidism
*Myocardial infarction
*Smoking
*Exercise
*Cardiothoracic surgery
*Increased pulse pressure
*European ancestry
*Family history
43
Atrial Fibrillation characteristics
Ventricular and atrial rate: Atrial rate is 300 to 600 bpm; ventricular rate is usually 120 to 200 bpm in untreated atrial fibrillation
Ventricular and atrial rhythm: Highly irregular
QRS shape and duration: Usually normal, but may be abnormal
P wave: No discernible P waves; irregular undulating waves that vary in amplitude and shape are seen and referred to as fibrillatory or f waves
PR interval: Cannot be measured
P:QRS ratio: Many:1
44
What are patients with fib at increased risk for?
heart failure, myocardial ischemia, and embolic events such as stroke
45
Medical Management of AFib
Medical management revolves around preventing embolic events such as stroke with anticoagulant medications, controlling the ventricular rate of response with antiarrhythmic agents, and treating the arrhythmia as indicated so that it is converted to a sinus rhythm
46
Atrial Flutter
occurs because of a conduction defect in the atrium and causes a rapid, regular atrial impulse at a rate between 250 and 400 bpm
47
Atrial Flutter Characteristics
Ventricular and atrial rate: Atrial rate ranges between 250 and 400 bpm; ventricular rate usually ranges between 75 and 150 bpm
Ventricular and atrial rhythm: The atrial rhythm is regular; the ventricular rhythm is usually regular but may be irregular because of a change in the AV conduction
QRS shape and duration: Usually normal, but may be abnormal or absent
P wave: Saw-toothed shape; these waves are referred to as F waves
PR interval: Multiple F waves may make it difficult to determine the PR interval
P:QRS ratio: 2:1, 3:1, or 4:1
48
Medical Management of Aflutter
Medical management involves the use of vagal maneuvers (see previous discussion under Sinus Tachycardia) or a trial administration of adenosine, which causes sympathetic block and slowing of conduction through the AV node.
49
Classic S/S of Infective (Bacterial Infection) Endocarditis
Splinter hemorrhages
Osler's Nodes (hands)
Janeway Lesions - hands and feet - autoimmune response
Roth Spots (eyes) - retina hemorrhage
50
Complications to monitor for in endocarditis
Stroke - mold that breaks off and travels and clogs the arteries of the brain
Monitor change in consciousness (confusion, weakness, etc)
51
Causes for Endocarditis
Bacterial Infection - IV drugs and dirty needles
Valve replacement surgery
Dental visits (oral)
52
Cardiomyopathy
Disease of the heart muscle (myocardium) which INHIBITS effective pumping
essentially - heart pumping problems
53
Dilated Distended Heart Muscle
Heart is stretched out and valves do not close all the way resulting in an ineffective pump
Less blood being pumped out into the heart meaning less oxygen
Low BP
MOST COMMON
54
Dilated Cardiomyopathy S/S
Low Oxygen
SOB
Fatigue
Angina and ECG (heart block)
Weak crackles in the lung
Narrowed pulse pressure
Murmur near S3 location
REMEMBER = LOW CARDIAC OUTPUT
Early symptoms of low O2:
restlessness
agitation
55
Heart failure - LEFT pump failure
Left Heart Failure = lungs filled with fluids
Crackles and pulmonary edema
56
Heart failure - RIGHT pump failure
Right Heart Failure = Rocks body with fluid
Edema, ascites (a condition in which fluid collects in spaces within your abdomen), JVD
57
Dilated Cardiomyopathy Diagnostic Test
Chest Xray = enlarged heart
Echocardiography = dilated and distended heart (how thin the muscle is)
Angiography = inject dye into the vein to see blockage
58
Ejection Fraction
55-70% is NORMAL
40% or less is BAD - indicates HF
59
Hallmark Cardiac Drugs
A = Ace Inhibitors - end in -pril, Lisinopril: drop the bp and take pressure off the heart; A = anti hypertension
B = Beta blocker - end in -lol, Atenolol: block beats in the heart by slowing it down; B = pumping the BREAKS
C = Calcium Channel Blockers; end in -dipine, -zem , -amil ; C= calms the heart
D = Digoxin - increases contractility; D = deep contraction
D = Diuretics - loop or thiazide; furosemide - dehydrate the body and decrease the bp - potassium wasting medications
All calm the heart and drop the blood pressure or heart rate
60
Monitor for digoxin toxicity
Apical Pulse - assess for full 60 seconds - under 60 bpm is not good
Potassium levels - under 3.5 not good
Digoxin level toxicity over 2.0 - vision changes, Nausea, Vomiting, fatigue, dizzy
HOLD IF THESE ARE THE CASE
61
What is a potassium wasting medication mean?
Medication dumps potassium from the water and into the potty
62
Hypertrophic Cardiomyopathy
MOST DEADLIEST
Genetic condition, heart becomes thick and hard and limits the heart from filling
Less Cardiac Output = Less O2 out
During strenuous activity caused more bulging of the heart muscle and oxygen is blocked from going out to the body
63
Hypertrophic Cardiomyopathy S/S
Asymptomatic - No s/s
only occurs when strain but on the heart
Low O2
SOB and fatigue
Altered consciousness
angina
sudden death
64
First - Degree Atrioventricular Block
block occurs when all the atrial impulses are conducted through the AV node into the ventricles at a rate slower than normal.
65
Second - Degree Atrioventricular Block Type I
occurs when there is a repeating pattern in which all but one of a series of atrial impulses are conducted through the AV node into the ventricles (e.g., every four of five atrial impulses are conducted)
66
Second - Degree Atrioventricular Block Type II
occurs when only some of the atrial impulses are conducted through the AV node into the ventricles.
67
Third - Degree Atrioventricular Block
occurs when no atrial impulse is conducted through the AV node into the ventricles. In third-degree AV block, two impulses stimulate the heart: one stimulates the ventricles, represented by the QRS complex, and one stimulates the atria, represented by the P wave.
68
Oxygen Delivery Method - Nasal Cannula
Nasal cannulas are the most widely used method of delivering oxygen.
At 1L/min nasal cannulas deliver an FiO2 of 24%, adding 4% every 1L added
Can use up to 6L/min for an FiO2 of 44%
Oxygen should be humidified
69
Oxygen Delivery Method - Simple Mask
Can deilver an FiO2 of 40-60% oxygen with a flow of 6-12 L/min
can be used for patients in mild respiratory distress
If a simple mask has a reservoir bag on it, it is called a partial rebreather mask
**partial rebreather masks can deliver an FiO2 of 50-60%
70
Oxygen Delivery Method - Non-rebreather mask
Valves prevent room air from coming into the system
This method silvers an FiO2 up to 95% at 8-15 L/min
71
Oxygen Delivery Method - Venturi
used to deliver a precise FiO2 to the patient ranging from 24-60%
an air entrainer that allows oxygen to be mixed with the room air
72
The nurse is preparing a male patient to have a 12-lead ECG performed. When prepping the skin the nurse notices that the patient has abundant chest hair. What is the most appropriate nursing intervention to improve adhesion of the ECG leads?
Clip the chest hair with the patient’s permission before applying the leads
Rationale: Clipping the patient’s hair would provide access to the skin to assist with adhesion. Alcohol should not be used to prep the skin because it increases the skin’s electrical impedance, thereby hindering the detection of the cardiac electrical signal. The ECG would not be performed correctly if the leads were only placed on the extremities, and there is no need to reschedule the ECG at this time
73
Collaborative Problems and Potential Complications
Cardiac arrest
Heart failure
Thromboembolic event, especially with atrial fibrillation
74
Collaborative Problems and Potential Complications
Cardiac arrest
Heart failure
Thromboembolic event, especially with atrial fibrillation
75
Nursing Intervention: Monitor and Manage the Arrhythmia
Assess vital signs on an ongoing basis
Assess for lightheadedness, dizziness, fainting
If hospitalized
- Obtain 12-lead ECG
- Continuous monitoring
- Monitor rhythm strips periodically
Antiarrhythmic medications
- “6-minute walk test”
76
The nurse is assessing a patient admitted with a heart block. When placed on a monitor, the patient’s electrical rhythm displays as progressively longer PR durations until there is a nonconducted P wave. Which type of heart block does the nurse expect that this patient has?
Second-degree, type 1
Rationale: In second-degree, type 1 AV block, the PR interval becomes longer with each succeeding ECG complex until there is a P wave not followed by a QRS. The changes in the PR interval are repeated between each “dropped” QRS, creating a pattern in the irregular PR interval measurements. In first-degree heart block, the PR is constant but greater than 0.20 seconds. Second-degree AV block, type 2 has a constant PR interval and the presence of more P waves than QRS complexes. Third-degree AV block presents with irregular PR intervals.
77
Complications of Pacemaker Use
Infection
Bleeding or hematoma formation
Dislocation of lead
Skeletal muscle or phrenic nerve stimulation
Cardiac tamponade
Pacemaker malfunction
78
Ventricular tachycardia (V-Tach) is characterized by
absent P waves, wide QRS complexes and a rate between 100 and 250 impulses per minute.
79
An emergent complication associated with a chest stab wound is
Cardiac tamponade
80
Cardiac tamponade
serious medical emergency in which blood or other fluids fill the pericardial space (the sac that surrounds the heart).
81
Which is an example of a cardiac arrhythmia that can occur when there are issues with the electrical impulses that stimulate each heart beat?
complete heart block
82
Afib s/s
COLLAPSED
Low oxygen causes
Chest pain
SPo2 lower
Low BP
Lethargic
Anxiety
palpations - tachycardia
83
Electrical Problem - Heart Attack
Pumping Problem
84
Electrical Problem - Cardiac Arrest
Electrical Problem
85
Coronary Atherosclerosis
Atherosclerosis is the abnormal accumulation of lipid deposits and fibrous tissue within arterial walls and lumen
86
The nurse is caring for a patient with
hypercholesterolemia who has been prescribed
atorvastatin (Lipitor). What serum levels should be
monitored in this patient?
A. Complete blood count (CBC)
B. Blood cultures
C. Na and K levels
D. Liver enzymes
D. Liver enzymes
Rationale: Atorvastatin (Lipitor) is an HMG-CoA
reductase inhibitor and is hepatotoxic. Therefore, liver
enzymes should be monitored in patients taking this
medication.
87
Angina Pectoris
A syndrome characterized by episodes or
paroxysmal pain or pressure in the anterior chest
caused by insufficient coronary blood flow
88
The nurse is caring for a patient who has severe chest
pain after working outside on a hot day and is brought
to the emergency center. The nurse administers
nitroglycerin to help alleviate chest pain. Which side
effect should concern the nurse the most?
A. Dry mucous membranes
B. Heart rate of 88 bpm
C. Blood pressure of 86/58 mm Hg
D. Complaints of headache
C. Blood pressure of 86/58 mm Hg
Rationale: Nitroglycerin dilates vessels in the body.
Dilation of the veins causes venous pooling of blood
throughout the body. As a result, less blood returns to
the heart, and filling pressure (preload) is reduced. If
the patient is hypovolemic, the decrease in filling
pressure can cause a significant decrease in cardiac
output and blood pressure. This patient was working
outside on a hot day, and the possibility of
dehydration and hypovolemia should be considered.
Dry mucous membranes can cause poor absorption of
sublingual nitroglycerin but is not the most
concerning. B and D are insignificant findings.
89
The nurse is caring for a patient after cardiac surgery.
Which nursing intervention is appropriate to help
prevent complications arising from venous stasis?
A. Encourage crossing of legs
B. Use pillows in the popliteal space to elevate the
knees in the bed
C. Discourage exercising
D. Apply sequential pneumatic compression devices as
prescribed
D. Apply sequential pneumatic compression devices as
prescribed
Rationale: Sequential pneumatic compression devices
should be used when prescribed to help prevent
venous stasis and clotting complications such as deep
vein thrombosis and pulmonary embolism. Patients
should be discouraged to cross their legs. Pillows
should not be used in the popliteal space to elevate
the knees; rather, this should be avoided. Exercises,
passive and active, should be encouraged.
90
Regurgitation
The valve does not close properly,
and blood backflows through the valve
91
Stenosis
The valve does not open completely, and
blood flow through the valve is reduced
92
Valve prolapse
The stretching of the valve leaflet
into the atrium during systole
