Transcript Assessment of the Cardiovascular System

Assessment of the
Cardiovascular System
Surface anatomy of the heart
The human heart is a cone-shaped,
hollow, muscular organ located in the
mediastinum between the lungs.
 It is approximately the size of an adult fist.
 The heart rests on the diaphragm, tilting
forward and to the left in the client's
chest.
 Each beat of the heart pumps
approximately 60 mL of blood, or
approximately 5 L/min.
 During strenuous physical activity, the
heart can double the amount of blood
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RIGHT SIDE
 The right atrium is a thin-walled structure that receives
deoxygenated venous blood (venous return) from all peripheral
tissues by way of the superior and inferior venae cavae and from
the heart muscle by way of the coronary sinus. Most of this venous
return flows passively from the right atrium, through the opened
tricuspid valve, and to the right ventricle during ventricular diastole,
or filling. The remaining venous return is actively propelled by the
right atrium into the right ventricle during atrial systole, or
contraction.
 The right ventricle is a flat muscular pump located behind the
sternum. The right ventricle generates enough pressure
(approximately 25 mm Hg) to close the tricuspid valve, open the
pulmonic valve, and propel blood into the pulmonary artery and the
lungs. The workload of the right ventricle is light compared with
that of the left ventricle because the pulmonary system is a lowpressure system, which imposes less resistance to flow
LEFT SIDE
 After blood is reoxygenated in the lungs, it flows freely
from the four pulmonary veins into the left atrium. Blood
then flows through an opened mitral valve into the left
ventricle during ventricular diastole.
 When the left ventricle is almost full, the left atrium
contracts, pumping the remaining blood volume into the
left ventricle. With systolic contraction, the left ventricle
generates enough pressure (approximately 120 mm Hg)
to close the mitral valve and open the aortic valve. Blood
is propelled into the aorta and into the systemic arterial
circulation
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Blood is propelled from the aorta throughout the
systemic circulation to the various tissues of the body;
blood returns to the right atrium because of pressure
differences.
The pressure of blood in the aorta of a young adult
averages approximately 100 to 120 mm Hg, whereas the
pressure of blood in the right atrium averages about 0 to
5 mm Hg. These differences in pressure produce a
pressure gradient, with blood flowing from an area of
higher pressure to an area of lower pressure.
The heart and vascular structures are responsible for
maintaining these pressures
Blood flow through the heart
ATRIOVENTRICULAR VALVES
 The AV valves separate the atria from the ventricles.
 The tricuspid valve is composed of three leaflets and
separates the right atrium from the right ventricle.
 The mitral (bicuspid) valve is composed of two leaflets
and separates the left atrium from the left ventricle
 During ventricular diastole, the valves act as funnels and
facilitate the flow of blood from the atria to the
ventricles. During systole, the valves close to prevent the
backflow (regurgitation) of blood into the atria
SEMILUNAR VALVES
 There are two semilunar valves: the pulmonic valve and
the aortic valve.
 The pulmonic valve separates the right ventricle from the
pulmonary artery.
 The aortic valve separates the left ventricle from the
aorta.
 Each semilunar valve consists of three cuplike cusps, or
pockets, around the inside wall of the artery. These
cusps prevent blood from flowing back into the ventricles
during ventricular diastole. During ventricular systole,
these valves are open to permit blood flow into the
pulmonary artery and the aorta
Coronary arterial system
LEFT CORONARY ARTERY
 The LCA divides into two branches: the left anterior descending
(LAD) and the circumflex coronary artery (LCX). The LAD branch
descends toward the anterior wall and the apex of the left ventricle.
It supplies blood to portions of the left ventricle, ventricular septum,
chordae tendineae, papillary muscle, and right ventricle.
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The LCX descends toward the lateral wall of the left ventricle and
apex. It supplies blood to the left atrium, the lateral and posterior
surfaces of the left ventricle, and sometimes portions of the
interventricular septum. In 45% of people, the LCX supplies the
sinoatrial (SA) node, and in 10% of people it supplies the AV node.
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Peripheral branches (diagonal and obtuse marginal) arise from the
LAD and LCX and form an abundant network of vessels throughout
the entire myocardium
RIGHT CORONARY ARTERY
 The RCA originates from the right sinus of
Valsalva, encircles the heart, and descends
toward the apex of the right ventricle.
 The RCA supplies the right atrium, right
ventricle, and inferior portion of the left
ventricle.
 In most people (more than 50%), the RCA
supplies the SA node and the AV node.
 Considerable variation in the branching
pattern of the coronary arteries exists
among individuals
Conduction system of the heart
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The cardiac conduction system is composed of specialized tissue
capable of rhythmic electrical impulse formation. It can conduct
impulses much more rapidly than other cells located in the
myocardium.
The SA node, located at the junction of the right atrium and the
superior vena cava, is considered the main regulator of heart rate.
The SA node is composed of pacemaker cells, which spontaneously
initiate impulses at a rate of 60 to 100 times per minute and
myocardial working cells, which transmit the impulses to the
surrounding atrial muscle
An impulse from the SA node initiates the process of depolarization
and hence the activation of all myocardial cells. The impulse travels
through both atria to the atrioventricular (AV) node located in the
junctional area. After the impulse reaches the AV node, conduction
of the impulse is delayed briefly. This delay allows the atria to
contract completely before the ventricles are stimulated to contract.
The intrinsic rate of the AV node is 40 to 60 beats/min.
The Bundle of His is a continuation of the AV node and is
located in the interventricular septum. It divides into the
right and left bundle branches.
 The bundle branches extend downward through the
ventricular septum and fuse with the Purkinje fiber
system.
 The Purkinje fibers are the terminal branches of the
conduction system and are responsible for carrying the
wave of depolarization to both ventricular walls. Purkinje
fibers can act as an intrinsic pacemaker, but their
discharge rate is only 20 to 40 beats/min.
 Thus these intrinsic pacemakers seldom initiate an
electrical impulse
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Mechanical properties of the heart
The electrical and mechanical properties of cardiac
muscle determine the function of the cardiovascular
system. The heart is able to adapt to various
pathophysiologic conditions (e.g., stress, infections, and
hemorrhage) to maintain adequate blood flow to the
various body tissues.
 Blood flow from the heart into the systemic arterial
circulation is measured clinically as cardiac output (CO),
the amount of blood pumped from the left ventricle each
minute. CO depends on the relationship between heart
rate (HR) and stroke volume (SV); it is the product of
these two variables:
 Cardiac output = Heart rate x Stroke volume
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CARDIAC OUTPUT AND CARDIAC
INDEX
 Cardiac output (CO) is the volume of
blood (in liters) ejected by the heart each
minute. In adults, the CO ranges from 4 to
7 L/min.
 Because cardiac output requirements vary
according to body size, the cardiac index
is calculated to adjust for differences in
body size.
 The cardiac index can be determined by
dividing the CO by the body surface area.
HEART RATE
 Heart rate refers to the number of times the ventricles contract each
minute. The normal resting heart rate for an adult is between 60 and 100
beats/min. Increases in heart rate increase myocardial oxygen demand.
 Heart rate is extrinsically controlled by the autonomic nervous system,
which adjusts rapidly when necessary to regulate cardiac output. The
parasympathetic system slows the heart rate, whereas sympathetic
stimulation has an excitatory effect. An increase in circulating endogenous
catecholamine (e.g., epinephrine and norepinephrine) usually causes an
increase in heart rate, and vice versa.
 Other factors, such as the central nervous system (CNS) and baroreceptor
(pressoreceptor) reflexes, influence the effects of the autonomic nervous
system on heart rate. Pain, fear, and anxiety can increase heart rate.
 The baroreceptor reflex acts as a negative-feedback system. If a client
experiences hypotension, the baroreceptors in the aortic arch sense a
lessened pressure in the blood vessels. A signal is relayed to the
parasympathetic system to have less of an inhibitory effect on the sinoatrial
(SA) node; this results in a reflex increase in heart rate
STROKE VOLUME
 Stroke volume is the amount of blood
ejected by the left ventricle during each
systole. Several variables influence stroke
volume and, ultimately, CO.
 These variables include heart rate,
preload, afterload, and contractility
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PRELOAD
Preload refers to the degree of myocardial fiber stretch at the end of
diastole and just before contraction. The stretch imposed on the
muscle fibers results from the volume contained within the ventricle
at the end of diastole. Preload is determined by left ventricular enddiastolic (LVED) volume.
An increase in ventricular volume increases muscle fiber length and
tension, thereby enhancing contraction and improving stroke
volume.
This statement is derived from Starling's law of the heart: the more
the heart is filled during diastole (within limits), the more forcefully
it contracts.
However, excessive filling of the ventricles results in excessive LVED
volume and pressure and a decreased cardiac output
AFTERLOAD.
Afterload is the pressure or resistance that the ventricles
must overcome to eject blood through the semilunar
valves and into the peripheral blood vessels. The amount
of resistance is directly related to arterial blood pressure
and the diameter of the blood vessels.
 Impedance, the peripheral component of afterload, is
the pressure that the heart must overcome to open the
aortic valve. The amount of impedance depends on
aortic compliance and total systemic vascular resistance,
a combination of blood viscosity and arteriolar
constriction.
 A decrease in stroke volume can result from an increase
in afterload without the benefit of compensatory
mechanisms
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CONTRACTILITY
 Contractility also affects stroke volume
and CO.
 Myocardial contractility is the force of
cardiac contraction independent of
preload.
 Contractility is increased by factors such
as sympathetic stimulation and calcium
release.
 Factors such as hypoxia and acidemia
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Structure of the capillary bed
Blood Pressure
Blood pressure is the force of blood
exerted against the vessel walls.
 The blood pressure in the arterial system
is determined primarily by the quantity of
blood flow or cardiac output (CO), as well
as by the resistance in the arterioles:
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Blood pressure = Cardiac output x
Peripheral vascular resistance
Blood Pressure Regulation
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Autonomic nervous system
– Baroreceptors
– Chemoreceptors
Renal system
 Endocrine system
 External factors also affect BP
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Venous System
Structure: a series of veins located
adjacent to the arterial system
 Function: completes the circulation
of blood by returning blood from the
capillaries to the right side of the
heart
 Cardiovascular changes in the older
adult: only evident when the person
is active or under stress
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Assessment Techniques
History
 Demographic data
 Family history and genetic risk
 Personal history
 Diet history
 Socioeconomic status
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Modifiable Risk Factors
Cigarette smoking
 Physical inactivity
 Obesity
 Psychological factors
 Chronic disease
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Pain or Discomfort
Pain or discomfort can result from
ischemic heart disease, pericarditis,
and aortic dissection.
 Chest pain can also result from
noncardiac conditions such as
pleurisy, pulmonary embolus, hiatal
hernia, and anxiety.
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Pain or Discomfort
(Continued)
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Terms such as discomfort, heaviness,
pressure, indigestion, aching,
choking, strangling, tingling,
squeezing, constricting, or vise-like
are all used to describe pain.
 Women often do not experience pain
in the chest but rather feelings of
discomfort or indigestion.
Pain Assessment
Onset
 Manner of onset
 Duration
 Frequency
 Precipitating factors
 Location
 Radiation
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(Continued)
Pain Assessment
(Continued)
Quality
 Intensity, which can be graded from
0 to 10, associated symptoms,
aggravating factors, and relieving
factors
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Dyspnea
Can occur as a result of both cardiac
and pulmonary disease
 Difficult or labored breathing
experienced as uncomfortable
breathing or shortness of breath
 Dyspnea on exertion (DOE)
 Orthopnea: dyspnea when lying flat
 Paroxysmal nocturnal dyspnea after
lying down for several hours
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Other Manifestations
Fatigue
 Palpitations
 Weight gain
 Syncope
 Extremity pain
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Physical Assessment
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General appearance
The nurse assesses the following areas: general build and
appearance, skin color, distress level, level of consciousness,
shortness of breath, position, and verbal responses.
Clients with chronic heart failure may appear malnoutrished, thin,
and cachectic.
Latent signs of severe heart failure are ascites, jaundice, and
anasarca (generalized edema) as a result of prolonged congestion of
the liver.
Heart failure may cause fluid retention, and clients may have
engorged neck veins and generalized dependent edema.
Coronary artery disease is suspected in clients with yellow, lipidfilled plaques on the upper eyelids (xanthelasma) or ear-lobe
creases.
Clients with poor cardiac output and decreased cerebral perfusion
may experience mental confusion, memory loss, and slowed verbal
responses
Physical Assessment
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Integumentary system
Skin color
– If there is normal blood flow or adequate perfusion to a given
area in light-colored skin, it appears pink, perhaps rosy in color,
and it is warm to the touch. Decreased flow is depicted as cool,
pale, and moist skin. Pallor is characteristic of anemia and can
be seen in areas such as the nail beds, palms, and conjunctival
mucous membranes
– A bluish or darkened discoloration of the skin and mucous
membranes in Caucasians is referred to as cyanosis. This
condition results from an increased amount of deoxygenated hemoglobin. Dark-skinned individuals may express cyanosis as a
graying of the same tissues
Physical Assessment
– Central cyanosis involves decreased oxygenation of the arterial
blood in the lungs and appears as a bluish tinge of the
conjunctivae and the mucous membranes of the mouth and
tongue. Central cyanosis may indicate impaired lung function or
a right-to-left shunt found in congenital heart conditions.
Because of impaired circulation, there is a marked desaturation
of hemoglobin in the peripheral tissues, which produces a bluish
or darkened discoloration of the nail beds, earlobes, lips, and
toes.
– Peripheral cyanosis occurs when blood flow to the peripheral
vessels is decreased by peripheral vasoconstriction. The
clamping down of the peripheral blood vessels results from a low
cardiac output or an increased extraction of oxygen from the
peripheral tissues. Peripheral cyanosis localized in an extremity is
usually a result of arterial or venous obstruction
Physical Assessment
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Skin temperature
– Skin temperature can be assessed for
symmetry by touching different areas of the
client's body (e.g., arms, hands, legs, and
feet) with the dorsal surface of the hand or
fingers.
– Decreased blood flow results in decreased
skin temperature. Skin temperature is lowered
in several clinical conditions, including heart
failure, peripheral vascular disease, and shock
Physical Assessment
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Extremities
– The nurse assesses the client's hands, arms, feet, and
legs for skin changes, vascular changes, clubbing,
capillary filling, and edema.
– Skin mobility and turgor are affected by the fluid
status of the client.
– Dehydration and aging reduce skin turgor, and edema
decreases skin mobility.
– Vascular changes in an affected extremity may
include paresthesia, muscle fatigue and discomfort,
numbness, pain, coolness, and loss of hair distribution
from a reduced blood supply
Physical Assessment
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Blood pressure
Normal blood pressure in adults older than 45 years of
age ranges from 90 to 140 mm Hg for systolic pressure
and from 60 to 90 mm Hg for diastolic pressure.
A blood pressure that exceeds 135/85 mm Hg increases
the workload of the left ventricle and oxygen
consumption.
A blood pressure less than 90/60 mm Hg may be
inadequate for providing proper and sufficient nutrition
to body cells. In certain circumstances, such as shock
and hypotension, the Korotkoff sounds are less audible
or are absent. In these cases the nurse might palpate
the blood pressure, use an ultrasonic device (Doppler
device), or obtain a direct measurement by arterial
catheter
Physical Assessment
Venous and arterial pulses: central and
jugular venous pressures, and jugular
venous distention
 The nurse observes the venous pulsations
in the neck to assess the adequacy of
blood volume and central venous pressure
(CVP). The nurse can assess jugular
venous pressure (JVP) to estimate the
filling volume and pressure on the right
side of the heart.
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Precordium
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Assessment of the precordium (area
over the heart) involves:
– Inspection
– Palpation
– Percussion
– Auscultation
 Normal heart sounds
 Paradoxical splitting
 Gallops and murmurs
 Pericardial friction rub
Normal heart sounds
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The first heart sound (S1) is created by the closure of
the mitral and tricuspid valves (atrioventricular valves).
When auscultated, the first heart sound is softer and
longer; it is of a low pitch and is best heard at the lower
left sternal border or the apex of the heart.
It may be identified by palpating the carotid pulse while
listening. S1 marks the beginning of ventricular systole
and occurs right after the QRS complex on the
electrocardiogram (ECG).
The first heart sound can be accentuated or intensified
in conditions such as exercise, hyperthyroidism, and
mitral stenosis.
A decrease in sound intensity occurs in clients with mitral
regurgitation and heart failure.
Normal heart sounds
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The second heart sound (S2) is caused mainly by the closing of the
aortic and pulmonic valves (semilunar valves).
S2 is characteristically shorter. It is higher pitched and is heard best
at the base of the heart at the end of ventricular systole.
The splitting of heart sounds is often difficult to differentiate from
diastolic filling sounds (gallops). A splitting of S1 (closure of the
mitral valve followed by closure of the tricuspid valve) occurs
physiologically because left ventricular contraction occurs slightly
before right ventricular contraction.
However, closure of the mitral valve is louder than closure of the
tricuspid valve, so splitting is often not heard.
Normal splitting of S2 occurs because of the longer systolic phase of
the right ventricle. Splitting of S1 and S2 can be accentuated by
inspiration (increased venous return), and it narrows during
expiration.
Abnormal heart sounds
PARADOXICAL SPLITTING.
 Abnormal splitting of S2 is referred to as
paradoxical splitting and is characteristic
of a wider split heard on expiration.
 Paradoxical splitting of S2 is heard in
clients with severe myocardial depression
that causes early closure of the pulmonic
valve or a delay in aortic valve closure.
 Such conditions include myocardial
infarction, left bundle branch block, aortic
stenosis, aortic regurgitation, and right
ventricular pacing.
Abnormal heart sounds
GALLOPS AND MURMURS.
 GALLOPS. Diastolic filling sounds (S3) and (S4) are produced when
blood enters a noncompliant chamber during rapid ventricular filling.
 The third heart sound (S3) is produced during the rapid passive
filling phase of ventricular diastole when blood flows from the
atrium to a noncompliant ventricle. The sound arises from vibrations
of the valves and supporting structures.
 The fourth heart sound (S4) occurs as blood enters the ventricles
during the active filling phase at the end of ventricular diastole.
 S3 is termed ventricular gallop, and S4 is referred to as atrial gallop.
 These sounds can be caused by decreased compliance of either or
both ventricles.
 The nurse can best hear left ventricular diastolic filling sounds with
the client on his or her left side. The bell of the stethoscope is
placed at the apex and at the left lower sternal border during
expiration.
Abnormal heart sounds
The auscultation of both S3 and S4, called
a summation or a quadruple gallop, is an
indication of severe heart failure.
 If the quadruple rhythm is present and the
client has tachycardia (a shortened
diastole), the two sounds may actually
fuse to produce a rhythm that sounds like
a horse galloping.
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Abnormal heart sounds
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MURMURS. Murmurs reflect turbulent blood flow through normal or
abnormal valves. They are classified according to their timing in the cardiac
cycle: systolic murmurs (e.g., aortic stenosis and mitral regurgitation) occur
between S1 and S2, whereas diastolic murmurs (e.g., mitral stenosis and
aortic regurgitation) occur between S2 and S1.
Murmurs can occur during presystole, midsystole, or late systole or diastole or can last throughout both phases of the cardiac cycle. They are
also graded according to their intensity, depending on their level of
loudness.
The nurse describes the location of a murmur by where it is best heard on
auscultation.
Some murmurs transmit or radiate from their loudest point to other areas,
including the neck, the back, and the axilla.
The configuration is described as crescendo (increases in intensity) or
decrescendo (decreases in intensity).
The quality of murmurs can be further characterized as harsh, blowing,
whistling, rumbling, or squeaking. They are also described by pitch, usually
high or low.
Abnormal heart sounds
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PERICARDIAL FRICTION RUB. A pericardial friction rub
originates from the pericardial sac and occurs with the movements
of the heart during the cardiac cycle. Rubs are usually transient and
are a sign of inflammation, infection, or infiltration.
Pericardial friction rubs may be heard in clients with pericarditis
resulting from myocardial infarction and cardiac tamponade.
The three phases of cardiac movement — atrial systole, ventricular
diastole, and ventricular systole — can produce three components of
a rub.
Usually only one or two components can be heard.
A short, high-pitched scratchy sound is produced with each
movement; the loudest component is heard in systole.
The nurse may be most able to auscultate the rubs when the client
sits, leans forward, and exhales.
A pericardial friction rub is better heard with the diaphragm of the
stethoscope.
Serum Markers of
Myocardial Damage
Troponin
 Creatine kinase
 Myoglobin
 Serum lipids
 Homocysteine
 C-reactive protein
 Blood coagulation tests
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Cardiac Catheterization
Client preparation
 Possible complications: myocardial
infarction, stroke, thromboembolism,
arterial bleeding, lethal
dysrhythmias, and death
 Follow-up care:
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– Restricted bedrest, insertion site
extremity kept straight
– Monitor vital signs
– Assess for complications
Other Diagnostic Tests
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Electrocardiography
The electrocardiogram (ECG) is a routine part of
every cardiovascular evaluation and is one of the
most valuable diagnostic tests.
Various forms are available: resting ECG,
continuous ambulatory ECG (Holter monitoring),
exercise ECG (stress test), and signal-averaged
ECG.
The resting ECG provides information about
cardiac dysrhythmias, myocardial ischemia, the
site and extent of myocardial infarction, cardiac
hypertrophy, electrolyte imbalances, and the
effectiveness of cardiac drugs.
A normal ECG pattern in lead II
Electrocardiography
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RESTING ELECTROCARDIOGRAPHY
The ECG graphically records the electrical current
generated by the heart. This current is measured by
electrodes that are placed on the skin and connected to
an amplifier and strip chart recorder.
In the standard 12-lead ECG, five electrodes attached to
the arms, legs, and chest measure current from 12
different views or leads: three bipolar limb leads, three
unipolar augmented leads, and six unipolar precordial
leads.
Placement of the leads allows the health care provider to
view myocardial electrical conduction from different axes
or positions, identifying sections of the heart in which
electrical conduction is abnormal.
Standard ECG limb leads
Unipolar augmented ECG leads
Unipolar precordial ECG leads
Electrocardiography
AMBULATORY ELECTROCARDIOGRAPHY
 Ambulatory ECG (also called Holter
monitoring) allows continuous recording of
cardiac activity during an extended period
(usually 24 hours) while the client is
performing his or her usual activities of
daily living (ADLs).
 The ambulatory ECG allows the
assessment and correlation of dyspnea,
chest pain, central nervous system
symptoms (e.g., lightheadedness and
syncope), and palpitations with actual
cardiac events and the client's activities.
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Other Diagnostic Tests
Electrophysiologic study
 Exercise electrocardiography
 Echocardiography
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– Pharmacologic stress echocardiogram
– Transesophageal echocardiogram
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Imaging
Components of a hemodynamic monitoring system
Hemodynamic Monitoring
Invasive system used in critical care
areas to provide quantitative
information about vascular capacity,
blood volume, pump effectiveness,
and tissue perfusion
 Pulmonary artery catheter
 Systemic intra-arterial monitoring
 Impedance cardiography
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