Nursing Care of Patients with Coronoary Vascular Disorders Flashcards
A hollow, muscular organ located in the center of the thorax occupying the space between the lungs (mediastinum) and rests on the diaphragm
Heart
Pumps blood to the tissues, supplying them with oxygen and other nutrients
Heart
Heart weighs approximately _____ ; the weight and size of the heart are influenced by age, gender, body weight, extent of physical exercise and conditioning, and heart disease
300 grams
the inner layer, consists of endothelial tissue and lines the inside of the heart and valves
Endocardium
the middle layer, made up of muscle fibers and is responsible for the pumping action
Myocardium
composed of specialized cells called _____ forming an interconnected network of muscle fibers encircling the heart in a figure-of-eight pattern that facilitates a twisting and compressive movement of the heart that begins in the atria
and moves to the ventricles as controlled by the cardiac conduction system
Cardiomyocytes
the exterior layer encased in a thin, fibrous sac called the pericardium
Epicardium
adheres to the epicardium
Visceral Pericardium
envelopes the visceral pericardium
Parietal Pericardium
a tough fibrous tissue that attaches to the great vessels, diaphragm, sternum, and vertebral column and supports the heart in the mediastinum
Visceral Pericardium
the space between these two layers normally filled with about 20 ml of fluid
Pericardial Space
the space between these two layers (visceral & parietal pericardium) normally filled with about _____ of fluid
20 ml
lubricates the surface of the heart
and reduces friction during systole
Pericardial Fluid
Thickness varies due to workload required by each chamber.
Heart Chambers
The myocardial layer of both atria is much _____ than that of the ventricles because there is little resistance as blood flows out of the atria and into the ventricles during diastole.
Thinner
Ventricular walls are much _____ than the atrial walls for it must overcome resistance to blood flow from the pulmonary and systemic circulatory systems during ventricular systole.
Thicker
The left ventricle is _____ more muscular than the right ventricle. It must overcome high aortic and arterial pressures, whereas the right ventricle contracts against a low-pressure system within the pulmonary arteries and capillaries.
2-3x
receives venous blood returning to the heart from the superior vena cava (head, neck, and upper extremities), inferior vena cava (trunk and lower extremities), and coronary sinus (coronary circulation)
Right Atrium
distributes venous blood (deoxygenated blood) to the lungs via the pulmonary artery (pulmonary circulation) for oxygenation
Right Ventricle
receives oxygenated blood
Left Atrium
from the pulmonary circulation via four pulmonary veins
Left Atrium
distributes oxygenated blood to the remainder of the body via the aorta (systemic circulation)
Left Ventricle
results from the ventricle’s close proximity to the chest wall, creating the pulsation created during normal ventricular contraction
Point of Maximal Impulse
Point of Maximal Impulse is located at the _____ of the left chest wall and the _____
Intersection of Midclavicular Line, Fifth Intercostal Space
allows flow of blood in only one direction
Valves of the Heart
composed of thin leaflets of fibrous tissue, open and close in response to the movement of blood and pressure changes within the chambers
Valves of the Heart
composed of thin leaflets of fibrous tissue, open and close in response to the movement of blood and pressure changes within the chambers
Valves of the heart
separates the atria from the ventricles
Atrioventricular valves
opens during diastole allowing the blood in the atria to flow freely into the relaxed
ventricles and closes when the ventricles contract and blood flows upward into the cusps of the tricuspid and mitral valves as ventricular systole begins
Atrioventricular valves
valve closes by _____ and the _____ preventing the backflow of blood into the atria (_____) as blood is ejected out into the pulmonary artery and aorta
Papillary Muscles, Chordae Tendinae, Regurgitation
composed of 3 cusps or leaflets
Tricuspid Valve
separates the left atrium from the left ventricle
Bicuspid/Mitral Valve
separates the right atrium from the right ventricle
Tricuspid Valve
composed of 2 cusps or leaflets
Bicuspid/Mitral Valve
composed of 3 leaflets, shaped like half moons
Semilunar Valves
closed during diastole and forced open during ventricular systole as blood is
ejected from the right and left ventricles into the pulmonary artery and aorta, respectively
Semilunar Valves
separates the right ventricle and the pulmonary artery
Pulmonic Valve
separates the left ventricle and the aorta
Aortic Valve
supplies arterial blood to the heart originating from the aorta just above the aortic valve leaflets
Coronary Arteries
Coronary arteries perfused during _____ unlike other arteries, thus a heart rate of 60-80 bpm provides an ample time during diastole for myocardial perfusion
Diastole
courses down the anterior wall of the heart
Left Anterior Descending Coronary Artery
circles around to the lateral left wall of the heart
Circumflex Artery
travels to the inferior wall of the heart
Right coronary artery
supplies the posterior wall of the heart
Posterior Descending Coronary Artery
located superficially to the coronary arteries
Coronary Veins
blood returns to the heart primarily through the coronary sinus located posteriorly in the
right atrium
Coronary Veins
generates and transmits electrical impulses that stimulate contraction of the myocardium
Cardiac Electrophysiology
Cardiac Electrophysiology first stimulates contraction of the _____ and then the _____
Atria, Ventricles
synchronization of the atrial and ventricular events allows the ventricles to fill completely before ventricular ejection, thereby maximizing cardiac output by two specialized
electrical cells: _____ and _____
Nodal Cells, Parkinje Cells
3 Characteristics of the Two Specialized Electrical Cells
Automaticity
Excitability
Conductivity
ability to initiate an electrical impulse
Automaticity
ability to respond to an electrical impulse
Excitability
ability to transmit an electrical impulse from once cell to another
Conductivity
the primary pacemaker of the heart composed of nodal cells located at the junction of the superior vena cava and the right atrium
Sinoatrial Node
SA node inherent firing rate of _____ impulses/beats per minute but may change the rate changes in response to the metabolic demands of the body
60 - 100
initiated electrical impulses are conducted along the myocardial cells of the atria via specialized tracts called _____ causing electrical stimulation and subsequent contraction of the atria and conducted to the AV Node
Internodal pathways
the secondary pacemaker of the heart composed of nodal cells located in the right atrial wall near the tricuspid valve
Atrioventricular node
coordinates the incoming electrical impulses from the atria and after a slight delay (allowing the atria time to contract and complete ventricular filling) relays the impulse to the ventricles
Atrioventricular node
AV Node inherent firing rate of ____ impulses/beats per minute
40-60
AV nodes conducts impulses through a bundle of specialized conducting tissue (_____) that divides into the _____ (conducting impulses to the right ventricle) and the _____ (conducting impulses to the left ventricle). The left bundle branch will further branch out into the _____
and _____ bundle branches
Bundle of His, Right Bundle Branch, Left Bundle Branch, Left Anterior, Left Posterior
Impulses travel through the bundle branches to reach the terminal point in the conduction system, the _____.
Purkinje Fibers
the terminal point in the conduction system
Purkinje fibers
composed of Purkinje cells that rapidly conduct impulses throughout the thick walls of
the ventricles stimulating the ventricular myocardial cells to contract
Purkinje Fibers
Purkinje Fibers inherent firing rate of _____ impulses/beats per minute
30-40
non-invasive graphic recording of the heart’s electrical activity
Electrocardiogram
recording electrical impulse that travels through the heart can be viewed by means of _____
Electrocardiography
Electrocardiogram reflects the _____ in specific waveforms on the screen of a cardiac monitor or on a strip of ECG graph paper
Phases of the Cardiac Cycle
1 small box - Amplitude _____ mV
.1
1 small box - Height _____ mm
1
1 small box - Duration _____ seconds
0.04
1 large box - Amplitude _____ mV
.5
1 large box - Height _____ mm
5
1 large box - Duration _____ seconds
.20
1 large box - _____ small boxes
25
Standard height _____ mm (_____ small boxes)
10, 10
Standard Amplitude _____ mV (_____ small boxes)
1, 10
1 second strip _____ small boxes / _____ large boxes
25, 5
6 second strip _____ large boxes / _____ small boxes
30, 150
represents the electrical impulse starting in the SA node and spreading through the atria (atrial depolarization)
P Wave
P Wave Height _____ mm or less (_____ small boxes)
2.5, 2 1/2
P Wave Duration _____ seconds or less (_____ small boxes)
.11, <3
reflects ventricular depolarization
QRS Complex
QRS Complex Duration _____ seconds (_____ small boxes)
<.12, <3
Not all _____ have all three waveforms
QRS Complex
QRS Waveforms are _____, small letters are used (q,r,s) if QRS waveforms are _____, capital letters are used (Q,R,S)
less than 5 mm, more than 5 mm (?)
first negatively deflecting waveform after P wave
Q wave
Less than 25% of the R wave amplitude
Q wave
Q wave Duration _____ seconds (_____ small box)
<.04, <1
first positively deflecting waveform after P wave
R wave
first negatively deflecting waveform after R waveform
S wave
represents ventricular repolarization (simultaneously with atrial repolarization but is not visible on the ECG)
T wave
follows the QRS complex and is usually the same direction (deflection) as the QRS complex
T wave
represent the repolarization of the Purkinje Fibers
U wave
follows the T wave and is smaller than the P wave
U wave
a rare waveform, but may sometime appear in patients with hypokalemia, hypertension, or heart disease
U wave
represents the time needed for sinus node stimulation, atrial depolarization, and conduction through the AV node before ventricular depolarization
PR Interval
measured from the beginning of the P wave to the beginning of the QRS complex
PR Interval
PR Interval normal duration _____ seconds (_____ small boxes)
.12-.20, 3-5
represents early ventricular repolarization
ST segment
lasts from the end of the QRS complex to the beginning of the T wave
ST segment
represents the total time for ventricular depolarization and repolarization
QT interval
measured from the beginning of the QRS complex to the end of the T wave
QT interval
QT normal duration _____ seconds (_____ small boxes);
.32 - .40, 8-10
normal duration for QTc: males _____ seconds; females: _____ seconds)
.39 - .45, .39 - .46
measured from the end of the T wave to the beginning of the next P wave (isoelectric period)
TP Interval
TP Interval preferred reference for the _____
Isoelectric line
the period when no electrical activity is detected, the line on the graph remains flat
Isoelectric line
compared with ST segment to detect any changes
Isoelectric line
measured from the beginning of one P wave to the beginning of the next P wave
PP interval
PP wave used to determine _____ rate and rhythm
atrial
measured from one QRS complex to the next QRS complex
RR interval
RR wave used to determine _____ rate and rhythm
ventricular
a brief change in voltage (membrane potential) across the cell membrane of heart cells
Cardiac Action Potential
stimulates the myocytes causing contraction due to exchange of electronically charged
particles
Cardiac Action Potential
the repeated cycle of depolarization and repolarization
Cardiac Action Potential
return of ions to its resting state
repolarization
exchange of ions causes a positively charged intracellular space and a negatively charged extracellular space
depolarization
Depolarization _____ enters the cells; _____ exits the cells
NA+ & CA++, K+
Repolarization _____ enters the cells; _____ exits the cells
K+, NA+ & CA++
Initiated cellular depolarization; Na+ enters the cell
Phase 0
Early repolarization begins; K+ exits the cell
Phase 1
Rate of repolarization slows: Ca++
enters the cell
Phase 2/ Plateau Phase
Repolarization completed; Cell returns to resting state
Phase 3
Resting phase before the next depolarization
Phase 4
the brief period immediately following the response especially of a muscle or nerve before it recovers the capacity to make a second response
Refractory Period
the cell is completely unresponsive to any electrical stimulus; it is incapable of initiating an early depolarization
Effective Refractory Period
Effective Refractory Period corresponds to _____ of the cardiac action potential
Phase 0 to middle of Phase 3
in this period, if an electrical stimulus is stronger than normal, the cell may depolarize prematurely causing premature contractions, placing the patient at risk for dysrhythmias
Relative Refractory Period
the physical study of flowing blood and of all the solid structures (such as through which it flows
Cardiac Hemodynamics
refers to the events that occur in the heart from the beginning of one heartbeat to the next
Cardiac Cycle
number of cycles depends on the number of _____
heart rate
composed of major sequential events cause blood to flow through the heart due to
changes in chamber pressures and valvular function during diastole and systole
Cardiac Cycle
the total amount of blood ejected by one of the ventricles in liters per minute
Cardiac Output
resting adult is _____ L/min but varies greatly depending on the metabolic
needs of the body
4-6
Cardiac Output is computed by multiplying the _____ (the amount of blood ejected from one
of the ventricles per heartbeat. The average resting is about 60 to 130 mL) by the _____
Stroke Volume, Heart Rate
Too much effort will result in fatigue, sometimes leading to a complete collapse, with the need to slow down substantially or even to stop.
Contractility
the degree of stretch of the ventricular cardiac muscle fibers at the end of diastole
Preload
an intrinsic property of myocardial cells is that the force of their contraction depends on the length to which they are stretched: the greater the stretch (within certain limits), the greater the force of contraction - preload value will eventually be reached at which cardiac output will no longer increase
Frank Starling or Starling Law
the force against which the ventricles must act in order to eject blood, and is largely dependent on the arterial blood pressure and vascular tone
Afterload
has an inverse relationship with stroke volume, is increased by arterial
Afterload
vasoconstriction, which leads to decreased stroke volume. The opposite is true with arterial vasodilation, in which case it is reduced because there is less resistance to ejection, and stroke volume increases
Afterload
specific enzymes released from myocardial cells that become necrotic from prolonged ischemia or trauma that leaks into the interstitial spaces of the myocardium and are carried by the lymphatic system into general circulation, resulting to abnormally high levels of in serum blood samples
Cardiac Biomarkers
a protein which becomes elevated with any muscle damage
Myoglobin
Myoglobin elevates within ____ hours from damage, peaks at _____ hrs, and returns to normal within _____ days
1-4, 6-12, 1-2
not specific to the myocardium or cardiac muscle so it could be indicative
of other muscle damage
Myoglobin
isoenzyme released in the presence of ischemia within muscle tissue
CK-MB
not specific to cardiac muscle, but is more specific than myoglobin and highly likely to be elevated with cardiac ischemia
CK-MB
CK-MB begins to elevate within _____ hours, peaks at _____ hrs, and a _____ days to return to normal
6-12, 12-24, few
an enzyme specific to cardiac muscle that is released with ischemia and damage
Troponin I
the most consistently specific to cardiac muscle and, due to it’s trend timing, is the most reliable
Troponin I
Troponin I begins to rise within _____ hours, peaks at _____ hrs, and takes a couple of _____ to return fully to normal
4-6, 18, weeks
a lipid required for hormone synthesis and cell membrane formation
Cholesterol
calculated by adding the HDL, LDL, and 20% of the triglyceride level
Cholesterol
the primary transporter of cholesterol and triglycerides into the cell
Low Density Lipoprotein
results to deposition on the walls of arterial vessels
Low density Lipoprotein
transports cholesterol away from the tissue and cells of the arterial wall to the liver for excretion
High density Lipoprotein
composed of free fatty acids and glycerol, are stored in the adipose tissue and are a source of energy
Triglycerides
increase after meals and are affected by stress. Diabetes, alcohol use, and obesity can elevate triglyceride levels. These levels have a direct correlation with LDL and an inverse one with HDL
Triglycerides
a neurohormone that helps regulate BP and fluid volume
Brain Natriuretic Peptide
primarily secreted from the ventricles in response to increased preload with
resulting elevated ventricular pressure
Brain Natriuretic Peptide
