Cardiac system and Hyertension (Week 1) Flashcards
1
Q
Where is the heart located anatomically?
A
the mediastinal space of the thoracic cavity
2
Q
Where is the beating of the heart best felt?
A
The 5th intercostal space
3
Q
Point of maximal impulse (PMI)
A
The point where the apex of the heart is closest to the chest wall. This is where you auscultate the apical pulse. The left ventricle is the closest chamber to this point.
4
Q
The three layers of heart tissue
A
- Endocardium - Inner Lining
- Myocardium - Muscle tissue
- Epicardium - Fibrous outer layer
5
Q
What is the heart surrounded by?
A
The pericardial sac (The fourth layer)
6
Q
What is the function of the pericardial fluid?
A
Lubricates the space between the heart and the pericardial sac.
7
Q
What is the septum?
A
Divides the left and the right sides of the heart.
8
Q
Why are the walls of the ventricles thicker than that of the atria?
A
Because of the need for musculature to create blood pressure.
9
Q
Afterload
A
The peripheral resistance against which the left ventricle must pump.
the force the heart must pump against
to push blood out of the LV. The greater the volume
(preload) the greater the pressure needed to expel it.
As afterload increases, stroke volume decreases.
10
Q
Arterial Blood Pressure
A
A measure of the pressure exerted by blood against the walls of the arterial system.
11
Q
Cardiac Index (CI)
A
A measure of the cardiac output of a patient per square meter of body surface area.
12
Q
Cardiac Output (CO)
A
The total blood flow through the systemic or pulmonary circulation per minute; can be described as the stroke volume (amount of blood pumped out of the left ventricle per beat [~70 mL]) multiplied by the heart rate (HR) over 1 minute.
13
Q
Cardiac Reserve
A
The ability to respond to physiological demands (exercise, stress, hypovolemia) by increasing or decreasing cardiac output as much as three-fold or four-fold.
14
Q
Diastole
A
Relaxation of the myocardium.
Relaxation=filling
• Atria fill
• Ventricles fill
15
Q
Diastolic Blood Pressure
A
The residual pressure of the arterial system during ventricular relaxation.
16
Q
Ejection Fraction (EF)
A
The percentage of end-diastolic blood volume that is ejected during systole.
17
Q
Mean Arterial Pressure (MAP)
A
A measurement related to BP; calculated by adding the diastolic pressure to one third of the pulse pressure.
18
Q
Murmurs
A
Sounds produced by turbulent blood flow through the heart or the walls of large arteries.
19
Q
Point of Maximal Impulse (PMI)
A
The site on the chest wall at the fifth intercostal space, at which the thrust or pulsation of the left ventricle is most prominent.
20
Q
Preload
A
The volume of blood in the ventricles at the end of diastole, before the next contraction.
The force used to stretch the muscle fibers
at end diastole, the heart’s maximum fill point.
Preload is determined by venous return (volume) and
fiber length and ability to stretch. The amount a
balloon stretches when inflated represents preload.
21
Q
Pulse Pressure
A
The difference between the systolic and the diastolic pressures.
22
Q
Systole
A
Contraction of the myocardium.
• Atrial systole blood ejects
into ventricles
• Ventricular systole blood
ejects from ventricles to
enter into:
• pulmonary artery
• aorta
23
Q
Systolic Blood Pressure
A
The peak pressure exerted against the arteries when the heart contracts.
24
Q
baroreceptors
A
Specialized nerve cells, located in the carotid arteries and arch of the aorta, that are sensitive to stretching and, when stimulated by an increase in BP, send inhibitory impulses to the sympathetic vasomotor centre in the brainstem.
25
Blood Pressure
The force exerted by the blood against the walls of the blood vessel; must be adequate for tissue perfusion to be maintained during activity and rest.
26
Hypertension
Sustained elevation of blood pressure over more than one reading; in adults. Exists when systolic blood pressure (SBP) is equal to or greater than 140 mm Hg or diastolic blood pressure (DBP) is equal to or greater than 90 mm Hg.
27
Hypertensive crisis
A severe and abrupt elevation in blood pressure, arbitrarily defined as a diastolic blood pressure above 120 to 130 mm Hg.
28
Isolated Systolic Hypertension
A sustained elevation in systolic blood pressure equal to or greater than 160 mm Hg with a diastolic blood pressure less than 90 mm Hg.
29
Orthostatic Hypotension
A decrease of 20 mm Hg (or more) in systolic pressure or a decrease of 10 mm Hg (or more) in the diastolic pressure that occurs when an individual assumes a standing position.
30
Primary (Essential) Hypertension
Elevated blood pressure without an identified cause; accounts for about 90 to 95% of all cases of hypertension.
31
Secondary Hypertension
Hypertension for which there is a known cause; accounts for about 5 to 10% of all hypertension cases.
32
Systemic Vascular Resistance (SVR)
The force opposing the movement of blood within the blood vessels; the radius of the small arteries and arterioles is the principal factor determining vascular resistance.
33
Which of the following instructions given to a patient who is about to undergo Holter monitoring is most appropriate?
A) “You may remove the monitor only to shower or bathe.”
B) “You should connect the monitor whenever you feel symptoms.”
C) “You should refrain from exercising while wearing this monitor.”
D) “You will need to keep a diary of all your activities and symptoms.”
“You will need to keep a diary of all your activities and symptoms.”
A Holter monitor is worn for at least 24 hours while a patient continues with usual activity and keeps a diary of activities and symptoms. The patient should not take a bath or shower while wearing this monitor.
34
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The nurse is admitting a patient who is scheduled to undergo a cardiac catheterization. Which of the following allergies is most important for the nurse to assess before this procedure?
A. Iron
B. Iodine
C. Aspirin
D. Penicillin
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Iodine
The physician usually will use an iodine-based contrast to perform this procedure. Therefore it is imperative to know whether or not the patient is allergic to iodine or shellfish
35
The blood pressure of a 71-year-old patient admitted with pneumonia is 160/70 mm Hg. Which of the following is an age-related change that contributes to this finding?
A. Stenosis of the heart valves
B. Decreased adrenergic sensitivity
C. Increased parasympathetic activity
D. Loss of elasticity in arterial vessels
Loss of elasticity in arterial vessels
An age-related change that increases the risk of systolic hypertension is a loss of elasticity in the arterial walls. Because of the increasing resistance to flow, pressure is increased within the blood vessel and hypertension results
36
The nurse is providing care for a patient who has decreased cardiac output related to heart failure. The nurse recognizes that cardiac output is
A. calculated by multiplying the patient’s stroke volume by the heart rate.
B. the average amount of blood ejected during one complete cardiac cycle.
C. determined by measuring the electrical activity of the heart and the patient’s heart rate.
D. the patient’s average resting heart rate multiplied by the patient’s mean arterial blood pressure.
calculated by multiplying the patient’s stroke volume by the heart rate.
Cardiac output is determined by multiplying the patient’s stroke volume (SV) by heart rate (HR), thus identifying how much blood is pumped by the heart over a one-minute period. Electrical activity of the heart and blood pressure are not direct components of cardiac output.
37
Auscultation of a patient’s heart reveals the presence of a murmur. This assessment finding is a result of
A. increased viscosity of the patient’s blood.
B. turbulent blood flow across a heart valve.
C. friction between the heart and the myocardium.
D. a deficit in heart conductivity that impairs normal contractility.
Turbulent blood flow across a heart valve.
Turbulent blood flow across the affected valve results in a murmur. A murmur is not a direct result of variances in blood viscosity, conductivity, or friction between the heart and myocardium.
38
While assessing the cardiovascular status of a patient, the nurse performs auscultation. Which of the following practices should the nurse implement into the assessment during auscultation?
A. Position the patient supine.
B. Ask the patient to hold his or her breath.
C. Palpate the radial pulse while auscultating the apical pulse.
D. Use the bell of the stethoscope when auscultating S1 and S2.
Palpate the radial pulse while auscultating the apical pulse.
In order to detect a pulse deficit, simultaneously palpate the radial pulse when auscultating the apical area. The diaphragm is more appropriate than the bell when auscultating S1 and S2. A sitting or side-lying position is most appropriate for cardiac auscultation. It is not necessary to ask the patient to hold his or her breath during cardiac auscultation.
39
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A 59-year-old man has presented to the emergency department with chest pain. Which of the following components of his subsequent blood work is most clearly indicative of a myocardial infarction (MI)?
A. CK-MB
B. Troponin
C. Myoglobin
D. C-reactive protein
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Troponin
Troponin is the biomarker of choice in the diagnosis of myocardial infarction (MI), with sensitivity and specificity that exceed those of CK-MB and myoglobin. CRP levels are not used to diagnose acute MI.
40
A nurse is caring for a patient immediately following a transesophageal echocardiogram (TEE). Which of the following assessments are appropriate for this patient? (Select all that apply.)
A. Assess for return of gag reflex.
B. Assess groin for hematoma or bleeding.
C. Monitor vital signs and oxygen saturation.
D. Position patient supine with head of bed flat.
E. Assess lower extremities for circulatory compromise.
Assess for return of gag reflex.
The patient undergoing a TEE has been given conscious sedation and has had the throat numbed with a local anaesthetic spray, thus eliminating the gag reflex until the effects wear off. Therefore it is imperative that the nurse assess for gag reflex return before allowing the patient to eat or drink. Vital signs and oxygen saturation are also important assessment parameters resulting from the use of sedation. A TEE does not involve invasive procedures of the circulatory blood vessels. Therefore it is not necessary to monitor the patient’s groin or lower extremities in relation to this procedure.
41
Which of the following cardiovascular effects of aging should the nurse anticipate when providing care for older adults? (Select all that apply.)
A. Arterial stiffening
B. Increased blood pressure
C. Increased maximal heart rate
D. Decreased maximal heart rate
E. Increased recovery time from activity
A. Arterial stiffening
B. Increased blood pressure
D. Decreased maximal heart rate
E. Increased recovery time from activity
Well-documented cardiovascular effects of the aging process include arterial stiffening, possible increased blood pressure, and an increased amount of time that is required for recovery from activity. Maximal heart rate tends to decrease rather than increase with age.
42
Cardiac Valves
Tricuspid
Pulmonic
Mitral
Atrial
43
Chordae Tendonae
Strands of fibrous tissue that anchor the cusps of the mitral and tricuspid valves into the papillary muscles of the ventricles. This prevents eversion of the leaflets into the atria during ventricular contraction.
44
Semilunar valves
Pulmonic and aortic valves
45
What do the semilunar valves do
Prevent blood from regurgitating into the ventricles at the end of each ventricular contraction.
46
Order of Blood flow through the heart
- Right Atrium from vena cava and coronary sinus
- Through Tricuspid Valve into right ventricle
- Pulmonic Valve into pulmonary artery
- Left atrium from the pulmonary veins
- Mitral Valve
- Left Ventricle
- Aorta
47
Stroke Volume
amount of blood pumped out of the LV
with each beat, depends on preload, afterload, and
contractility
48
Contractility
is the ability of cardiac muscle cells to contract
or shorten after being stretched. The more the balloon
stretches the greater the contractility when the valve opens
49
Frank-Starling Law
* Describes the length-tension relationship of VEDV (preload) to myocardial contractility (Stroke Volume)
* Muscle fibers have optimal resting length to get maximum contractility
* Excessive fill (preload/VEDV) leads to fall in Stroke Volume
50
stroke volume of 70 ml/ min with heart rate of 72 beats/min
• What is the cardiac output?
• Is it in normal range?
0.07 L * 72bpm = 5.04 L/min
Normal: – 4 - 8 liters/minute.... so yes, it is normal
51
“Lub” S1
* Closing of the valves
* Between the atrium and the ventricle
* AV valves
52
“Dup” S2
* Closing of the aortic and pulmonic valves
| * Semilunar valves
53
automaticity
Cardiac muscle can transmit impulses automatically
54
Systole and Diastole depend on what?
Systole & Diastole depend on transmission of electrical impulses
55
What constitutes the conduction system?
* SA node “pacemaker” – sinoatrial node
* AV node – atrioventricular node
* Bundle of HIS
* Purkinje Fibers
* One will take over for another if needed
56
What is the inherent rate of the SA node?
Inherent rate 60-100 bpm
57
What is the inherent rate of the AV node?
Inherent rate 40-60 bpm
58
What is the inherent rate of the Purkinje Fibers?
Inherent rate 20-40 bpm
59
Cardiac Action Potentials
* Activation of the myocardium: DEPOLARIZATION
* Caused by electrically charged ions across cardiac cell membrane;
* Inside cell becomes less negative Membrane permeability to Na+ and K+ becomes disrupted resulting in depolarization
* Deactivation of myocardium: REPOLARIZATION
* Movement across the cell membrane is called “membrane potential”
60
P wave
Atrial Depolarizaton;
| begins with firing of the SA node
61
PR interval
represents travel from SA to AV to His-Purkinje
| 0.12-0.20 sec
62
QRS complex
ventricular depolarization and atrial repolarization
| 0.06 – 0.10 sec
63
T-wave
ventricular repolarization,
| tall and peaked, ?high K
64
U wave
May indicate electrolyte imbalance or repolarization abnormalities
65
What do vertical lines represent in an ECG?
Voltage
66
Where does S1 land on an ECG?
The peak of the QRS complex
67
Where does S2 land on an ECG?
Just after the T wave
68
What is the function of the coronary?
To perfuse the myocardium
69
Where do the coronary arteries branch from?
The Aortic Valve
70
When do the coronary arteries receive perfusion?
During diastole
71
In order to function, the heart requires a flow of blood separate from that that flows through its chambers. Flow through these coronary arteries and veins is known as...
Coronary Circulation
72
The vessels of the right coronary circulation system supply what?
nutrients to major nerve-impulse conduction centers in the heart. Because of this, right-sided blockage of blood flow is more likely to create
serious consequences.
73
What happens during systole in regards to the coronary circulation?
* Aortic valves obstruct flow to the coronaries; pushing against coronary arteries during ventricular contraction q(systole)
* Coronary arteries are compressed by ventricular contraction (systole)
* These features have a compression effect to DECREASE coronary blood flow; therefore, flow into the coronaries is diminished during SYSTOLE; increased during DIASTOLE.
74
Where does Venous coronary blood enter the RA?
Coronary sinus
75
Sympathetic Nervous System role in the Cardiovascular system?
• increases HR & impulse conduction through the AV node; increasing the FORCE of the Atrial & Ventricular contraction (Epi, Norepi, Ca++)
• SNS also has alpha/beta-adrenergic receptors on vasc. smooth muscle
• Increased stimulation = vasoconstriction
• Decreased stimulation= vasodilation
Fight or Flight
• Increased Heart Rate
• Increased Respiratory Rate
• Increased Blood Pressure
76
Parasympathetic Nervous System role in the Cardiovascular system?
```
• decreased HR and impulse conduction; slows conduction through AV node; WEAKENING force of
contractions (Acetylcholine)
• MEDIATED by the Vagus Nerve
Rest and Digest
• Decreased Heart Rate
• Decreased Respiratory Rate
• Decreased Blood Pressure
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77
Composition of vessel walls
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
78
Arteries
More elastic tissue, less smooth muscle tissue. Expansion and recoil buffer pressure surges and
propel blood forward.
79
Arterioles
Less elastic tissue, more smooth muscle tissue. The greater muscle content of arterioles makes
them the major “control mechanism” for blood-circuit distribution; it is their expansion and contraction that
dictates how blood flow volume variances occur.
80
Capillaries
Only a thin layer of endothelial cells. No elastic or muscle tissue.
81
Venules and Veins
Thin elastic walls, very little smooth muscle. Has backflow-preventing valves. Designed
for low-resistance blood return to the heart. * Blood flow through the veins depends largely upon their
surrounding skeletal muscle groups’ contractions and contractions of the thoracic cavity.
82
What is the main difference between the walls of the arteries and the veins
Veins have valves to prevent backflow of blood.
83
Composition of vessel walls
Endothelium - Tunica Intima
Valve (Vein only)
Elastic membrane (Thinner in vein)
Smooth Muscle layer - Tunica Media (Thinner in vein)
Connective Tissue - Tunica Adventitia (In artery, thinner than media, in vein thickest layer)
84
Hypertension exists when an individual has a sustained blood pressure of:
Systolic: ≥ 140mmHg
Diastolic: ≥ 90mmHg
85
Prehypertension (or high-normal) BP is classified as:
Systolic: 135 – 139 mmHg
Diastolic: 85-89 mmHg
86
High blood pressure puts the heart and blood vessels under greater stress than usual, and directly contributes to the development of:
1) MI
2) Stroke
3) Renal Failure
4) Atherosclerosis
87
Which population has a higher risk of hypertension?
Individuals of African or Aboriginal decent have a higher incidence of hypertension. **Blood pressure has a genetic (hereditary) component.
88
How does sex affect BP?
Hypertension is more prevalent in males in the under-55 age group, because estrogen contributes to lower BPs in women. After menopause, however, both are equal.
89
Two pressures exist that create blood pressure:
1) Cardiac Output (CO): forward pressure
2) Systemic (or peripheral) Vascular Resistance (SVR/PVR): opposing pressure.
The main component of systemic vascular resistance is the decreasing blood vessel diameters as blood
advances through the CV system.
90
Arterial diameters are controlled by...
the vasomotor centers in the brain in response to baroreceptors in the aortic arch and the carotid arteries (carotid sinus).
91
Regulation of blood pressure occurs by way of four body systems:
1) Nervous (Short-Term)
2) Cardiovascular (Short-Term)
3) Renal (Long-Term)
4) Endocrine (Long-Term)
92
How does the sympathetic nervous system respond to blood pressure?
In response to low blood pressure, the sympathetic nervous system accelerates the heart rate, causes widespread peripheral vasoconstriction, and stimulates the release of renin from the kidneys. In the case of high blood pressure, these responses are inhibited.
93
How does the body compensate for high blood pressure
Blood pressure may be reduced by either deactivation of the SNS or activation of the parasympathetic NS.
94
sympathetic nervous system activation
norepinephrine is released as both a neurotransmitter (directly from nerves) and a hormone (from the adrenal medulla). The neurotransmitter norepinephrine only affects the localized areas where it is released. The hormone norepinephrine causes generalized body responses.
95
Cardiac response to norepinephrine
Cardiac response to norepinephrine is mainly with its alpha-adrenergic receptors. Activation increases heart rate and heart contractility. In the blood vessels, beta-adrenergic receptors cause vasoconstriction.
96
Compounds can affect the heart in three ways:
1) Chronotopic effects alter heartrate.
2) Inotropic effects alter heart contractility.
3) Dromotropic effects alter nerve conductivity.
97
Renal response to high blood pressure
In response to low blood pressure sensed in the kidneys, renin is released from the juxtaglomerular apparatus.
98
How Renin converts angiotensinogen, produced by the liver, into angiotensin
1. Angiotensin 1 is converted by angiotensinconverting
enzyme (at the lungs) to angiotensin
2. *ACE-inhibitor medications inhibit this process, lowering blood pressure. Angiotensin 2 stimulates the release of aldosterone from the adrenal glands, increasing sodium and water retention to increase blood volume and pressure, respectively.
99
What are the effects of epinephrine in the heart?
In the heart, the effects of epinephrine are the same as norepinephrine; increased cardiac output. In most blood vessels, however, its effects are opposite, it causes vasodilation. Some vessels, however, such as in the skin and kidneys, will vasoconstrict when exposed to epinephrine. This difference of response is what determines the redistribution of blood flow with SNS activation (think fight or flight / stress response). Generally speaking, noncritical (for immediate survival)
organs vasoconstrict to reduce blood flow, and critical organs (heart/lungs/brain/skeletal muscles) will dilate to receive increased blood supply.
100
Primary hypertension is a symptom of many possible causes that are so complex they cannot be identified. Usually, it is a result of 1 or more of the following:
1) Overproduction of aldosterone or vasoconstrictors (smoking because nicotine is a vasoconstrictor).
2) Chronic stress.
3) Diabetes.
4) Excessive alcohol intake.
5) Obesity.
6) Excessive sodium intake.
101
Secondary hypertension
Secondary hypertension is much less common but often more acute and will have an identifiable origin.
102
Hypertension is often asymptomatic until it becomes severe. When symptoms do develop, they are generally due to overwork of the heart or damage to blood vessels and present as:
1) Fatigue
2) Activity Intolerance
3) Palpitations
4) Angina
5) Dyspnea
6) Dizziness
103
Chronic hypertension eventually progresses to specific-organ disease in:
1) The heart: Hypertensive heart disease.
2) The brain: Cerebrovascular disease.
3) Peripheral Vascular: PV disease.
4) Kidneys: Nephrosclerosis.
5) Eyes: Retinal damage.
104
Hypertensive heart disease has three forms:
1) Coronary artery disease: Atherolerosis in coronary arteries reduces coronary circulation; leads to angina or
MI.
2) Left ventricular hypertrophy: The left ventricle must consistently work harder to overcome the afterload;
the muscle gets bigger over time.
3) Heart failure: When the compensatory mechanisms of the heart (Chrono/Ino/Dromo –tropic) can no longer
meet the demands of the body, it is classified as heart failure. Observable as fatigue, shortness of breath,
dyspnea.
105
Cerebrovascular Disease
In the brain, atherosclerosis occurs mainly at the bifurication (division in to two) of the carotid artery into its internal and external branches. Pieces of the plaque buildup break off and move into the smaller vessels of the brain, blocking off blood flow. If the blockage is temporary, it is a transient ischemic attack. If it remains, it is an ischemic stroke. If the blockage causes a localized increase in blood pressure that breaks through the vessel wall, it is a hemorrhagic stroke.
106
Peripheral Vascular Disease
Atherosclerosis in the aorta can weaken the vessel wall causing aortic aneurism. It can also cause localized pain in skeletal muscles noticeable upon exertion.
107
intermittent claudication
ischemic muscle pain
108
Nephrosclerosis
Atherosclerosis in the arteries of the kidneys causes damage to the tubules, damage to the glomeruli, and eventual death of nephrons.
109
Retinal damage in hypertension
The retina is the only place in the body where the blood vessels can be observed directly with noninvasive methods. As such, changes in the vessels of the retina, observable by ophthalmoscope, provide key information regarding probable changes in other body blood vessels. Hypertensive damage to the retinal vessels can cause blurred vision, retinal hemorrhage, or loss of vision.
110
Hypertension Diagnostics
* Routine laboratory tests should be performed for the investigation of all patients with hypertension, including the following:
* Urinalysis
* Blood chemistry (potassium, sodium, and creatinine)
* Fasting blood glucose
* Fasting total cholesterol and high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides
* Standard 12-lead electrocardiography
* Assess urinary albumin excretion in patients with diabetes
* All patients with treated hypertension need to be monitored for the appearance of diabetes according to the Current Diabetes Association
111
Primary prevention of hypertension
Lifestyle changes, lowering risk factors.
112
Secondary prevention of hypertension
Diagnostics performed to screen for HTN.
113
Tertiary prevention of hypertension
Medical interventions aimed at preventing HTN-disease.
114
Lifestyle modifications should be aimed at...
Increasing exercise, healthy eating, moderation with alcohol usage, reducing dietary sodium intake, quitting smoking, and stress reduction.
115
What are hemodynamic variables that impact blood pressure?
* Cardiac output
* Vascular resistance
* Blood volume
* Viscosity
* Elasticity
116
Chronotropic
drugs that influence heart rate
117
Inotropic
drugs that influence contractility of heart muscle
118
Dromotropic
drugs that influence the conduction of electrical impulse
