Cardiovascular I
Blood flow through the Heart (Systemic Circulation)
a) Right Atrium receives blood from the vena cava and coronary sinus.
b) Blood passes from rt atrium through the tricuspid valve to right ventricle
c) From right ventricle- blood passes through the pulmonic valve into the pulmonary artery and to the
lungs for oxygenation.
d) Pulmonary __________
e) return freshly oxygenated blood back to the left atrium
▪ Blood flow through the Heart
(Systemic Circulation)
e) Blood passes from the left atrium to the left ventricle through the mitral valve.
f) Blood exits the left ventricle through the aortic valve out into the aorta and to the body,
g) A/V valves- tricuspid and bicuspid (aka mitral)
Semilunar valves- pulmonic and aortic
h) All valves are _____________________
Heart Valves….
▪Tissue (tricuspid)
▪Paper (pulmonic)
▪My (mitral)
▪Assets (aortic)
Myocardial Blood Supply – Blood flow through the
Heart (Coronary Circulation)
a) Has its own circulatory system
b) Right above the cusps of the aortic valve are the sinuses of Valsalva which open into the right and left
coronary artery
c) Blood flows during _______________
d) Right coronary artery- supplies right atrium and right ventricle (part of posterior left ventricle)
e) Left coronary artery – branches into the left anterior descending and the left circumflex artery that
supply the left atrium and left ventricle
Myocardial Blood Supply
(Coronary Circulation)
ISCHEMIA (tissue hypoxia) - inadequate blood flow to meet the myocardial O2 requirements.
The pain that goes along with myocardial ischemia is known as _________________
MYOCARDIAL INFARCTION (MI) is the result of permanent loss of blood supply and cellular
death (tissue necrosis).
Conduction System
a) SA node – specialized nerve tissue - the heart’s pacemaker.
b) Action potential – electrical impulse travels though heart & leads to contraction.
c) C occurs when calcium flows into cardiac cells after depolarization
▪Conduction System
d) AV node – allows time for atria to fill by providing a break in the contraction
e) Bundle of His – picks up the impulse and spreads it over the ventricles by way of the Purkinje
fibers
f) Repolarization – cells return to former state
g) Systole – absolute refractory period during which the cardiac muscle gradually recovers and is
excitable again
Electrocardiogram
▪AKA Ekg / ECG
EKG
1- P Wave = depolarization of the __________
2- PR interval = measure of the time required for the impulse to spread from the SA node to the
ventricle
3- QRS interval = depolarization of the ventricles
4- T Wave = repolarization of the ventricles
5- U wave = if present may mean hypokalemia or repolarization abnormalities
EKG Strips Normals…
EKG Strip:
Each small box 0.04 sec &
Each large box 0.20 sec)
P wave (normal) 0.06-0.12 sec
P-R interval (normal) __________ sec
QRS complex (normal) 0.04-0.12 sec
Identifying EKG Abnormalities
Measure Rate
Measure P to P for Atrial Rate
Measure R to R for Ventricular Rate
Measure Rhythm
Regular, Irregular, Regular Irregularity
P Wave Present
PR Interval
Measuring Rate:
Count each 6 second strip for number of complexes then ___________________ for 60 seconds
(1min) “rule of 10’s”
<60 BPM is bradycardia
60-100 BPM “normal” rate
> 100 BPM is tachycardia
Normal Sinus Rhythm (NSR)
1- Rate _____________ BPM
2- Rhythm is regular
3- SA node is initiating the beats
Sinus Tachycardia
1- Rate is ____________ BPM
2- Rhythm is regular ( check P to P and R to R intervals)
Sinus Bradycardia
1- Rate _____________ BPM
2 -Rhythm is regular ( p to p and r to r intervals are equal)
Atrial Flutter (A Flutter)
1 -Rate : the atria fire and contract 250-400 times per minute ( result of irritable atrial focus)
2- Appearance of ____________ waves…multiple discernable “p waves” for each QRS
3- Rhythm: can be regular or irregular
Atrial Fibrillation (A Fib)
1 -Rate: multiple foci or pacemakers fire in the atria at the same time resulting in chaotic impulses at a
rate of 400 or more per minute…the atria are essentially “quivering” not contracting.
2- NO discernable ___________________
3- rhythm is irregular
4- controlled A-Fib ventricular response rate
is <100, over 100 is uncontrolled a-fib
Ventricular Tachycardia (V-Tach)
1- Atrial rate not usually countable
2- Ventricular rate between 100-250 bpm
3- No consistent P waves associated with QRS
4- No PR interval
5- W________________, bizarre QRS complex ( >0.12 sec)
6- Rhythm- usually regular
Ventricular Fibrillation (V Fib)
Multiple areas within the ventricles fire at random, asynchronous times producing a chaotic
completely disorganized rhythm.
The ventricles are ____________________, not contracting.
No cardiac output, no pulse, and no BP
Rate- too fast to count
Rhythm- irregular
Absent P waves and PR interval unobtainable
EKG Strips Normals…
T Wave – Normal elevation vs:
ST Elevation = Myocardial Infarction
ST Depression = Myocardial Ischemia
Cardiac Output (C0)
(1) CO = amount of blood pumped per min (_________L/min)
(2) CO= Heart Rate x Stroke Volume (blood ejected per beat /mL)
Components of SV :
1. Preload
2 . Afterload
3. Contractility
Cardiac Output
▪If your HR is 70 bpm and your stroke volume
is 70 mL, what is your CO?
How does one increase their cardiac output?
Cardiac Output - Preload
The volume of blood in the ventricles at the end of diastole, before the next contraction is
preload.
Think of Preload as ________________
EDV- end diastolic volume
Preload determines the amount of “stretch” placed on the myocardial fibers.
Cardiac Output – Preload Effect
(volume/stretch)
You will see an ↑increase in Preload with:
(1)Hypervolemia / Fluid overload
(2) Cardiac valve regurgitation
(3)Pump failure/CHF
You will see a ↓ in Preload with:
(1) Low circulating blood volume / dehydration
(2) Bleeding
(3) Shock, hypovolemia
Cardiac Output - Afterload
▪Afterload: Reflects the ___________________ against which the left ventricle must push to
eject blood.
▪Affected by:
▪Size of ventricle, Vascular wall tension and arterial blood pressure
▪Afterload = VACULAR RESISTANCE
Cardiac Output – Afterload Effect
(vascular resistance)
Causes of Increased↑ Afterload:
Vasoconstriction
Hypertension
Meds that vasoconstrict
Causes of Decreased ↓ Afterload:
Vasodilation
Hypotension
Shock, vasodilatory
Cardiac Output – Contractility (Squeeze)
▪Contractility: speaks to how ________________ the muscle is.
▪When contractility ↑rises, the SV↑ rises by increasing the
emptying of the ventricles
▪ Increases ↑ with epinephrine/norepinephrine (SNS)
6. Cardiac Output - Contractility
(squeeze)
Increases Contractility:
I. Sympathetic nervous system
II. Positive inotropes
III. (Digoxin)
Decreases Contractility:
I. Age
II. HF- heart failure
Cardiac Output
▪Increasing preload, afterload, or contractility increases the work load of the heart and increases
the need for oxygen
Cardiac Output - Starling’s Law
To a point, the more the fibers are stretched, the greater their force of contraction.
(Frank Starling)
Regulation of Cardiovascular System
Autonomic Nervous System (ANS)
ANS
↙ ↘
SNS PNS
a) Sympathetic (__________________)
increases HR and
increases contractility
b) Parasympathetic (vagus nerve) decreases HR
c) Exercise, temperature, medications exert their effects on the
heart through the ANS
Regulation of Cardiovascular System
▪Baroreceptors:
Location: Aortic arch, carotid sinus, vena cava, atria, and pulmonary arteries:
Sense pressure changes within the _______________ system
Send messages to vasomotor center (brainstem)
↑ BP Inhibits sympathetic & enhances parasympathetic
↓ BP Enhances sympathetic & inhibits parasympathetic
▪Regulation of Cardiovascular System
Blood Pressure
The pressure exerted by blood against the walls of the arterial system
Systolic is the peak pressure against the arteries when the heart contracts.
Diastolic is the residual pressure during ventricular relaxation.
Measured invasively through arterial pressures(arterial catheter) or non-invasively (manual cuff)
▪Regulation of Cardiovascular System
Systolic BP – Maximum pressure exerted heart (120/80; SBP=120)
Diastolic BP – Minimum pressure exerted by heart (120/80; DBP=80)
Pulse Pressure (PP) = SBP-DBP (PP=120-80=40)
MAP( mean arterial etween SBP and DBP is the
pulse pressure) a “perfusion measure” MAP= SBP + 2xDBP
3
Normal value for MAP is _______________
*** MAP needs to be ≥60-65 to perfuse the vital organs***
Regulation of Cardiovascular System
Pulse Pressure
Pulse Pressure
The difference between systolic and diastolic BP
BP = 134/80: PP = 54
The normal range of pulse pressure is between __________________mm Hg.
Pulse pressure tends to increase after the age of 50. This is due to the stiffening of
arteries and blood vessels as you age.
Narrowing Pulse Pressure ( narrowed) causes:
Hypovolemia
Bleeding
Widened Pules Pressure (widened) can be seen with aging at baseline
Isolated systolic hypertension (ISH)
Increased Intracranial Pressure
New onset: can mean neurological emergency
Regulation of Cardiovascular System
Effects of aging on the CV system
1- Increased collagen in the heart muscle.
2- Valves acquire lipid and collagen accumulation
3- Decreased response of the heart to exercise
4- Decreased # of pacemaker cells
5- Decreased # of beta receptors
6- Decreased # of _____________ in arterial walls
7- Despite these changes, under normal circumstances, the heart functions well.
Regulation of Cardiovascular System
Non-invasive studies
Chest Xray – structural changes & size of heart
EKG -@ rest, stress test, or continuous monitoring
Echo- ultrasound of the heart ( LVEF % left ventricular ejection fraction) look at TEE
Nuclear Cardiology (radioactive isotope injected)
Calcium scoring CT scan
Invasive Studies
Cardiac Catheterization
Regulation of Cardiovascular System
Cardiac Markers
Enzymes- found in all cells and released into circulation when cells are injured
1-CRP c-reactive protein (normal < 1.0 mg/L) general inflammatory marker in the body but also released
when MI occurs
2-CK-MB (CK-2) Found primarily in cardiac muscle & cardiac nerve cells. Can rise within 4- 6 hrs of MI
(concentrations > 4-6% total CK indicative of MI)
3. Troponin I (normal ng/mL) – Golden Standard!!!
rises in 4-6 hr, peaks 10-24 hours, returns to normal in 4 days.
Highly specific to cardiac muscle. See levels in book.
Regulation of Cardiovascular System
Cardiac Markers
Lipids – total cholesterol < 200 mg/dL
LDL (< 130 mg/dL with <100 mg/dL ideal)
HDL >40 mg/dL men, >50 mg/dL women
Meds for Hyperlipidemia – review meds on table 33-5.
Most common:
Statins (Lipitor, Crestor, Zocor)
Niacin
Fibric Acid Derivatives (Lopid, Tricor)
Cardiac Catheterization
Right sided
Through a ______________
Measures R chamber pressures and pulmonary artery wedge pressures (PAWP)
Left sided
Accessed through an _____________ to LV
Evaluate chamber pressures and oxygen content
Coronary angiography – dye into vessels to visualize arteries on screen during cath
Cardiac Catheterization
Nursing Responsibilities
Pre-cath:
Teaching: procedure takes 2-3 hr, must be awake to cough and take deep breaths, heart
will flutter but on continuous ECG
Permission
NPO ___________ hr prior* unless emergent cath
Post-cath:
Peripheral pulses, warmth and color of extremities q 15 min x 1 hr then decreasing as
ordered
Assess for bleeding from the site
Assess respiratory status for PE
Assess for cardiac arrhythmias
Coronary
Artery
Disease
▪CAD
▪CAD - Definition
▪Type of blood vessel disorder in the general category of atherosclerosis
▪Derives from 2 Greek words
▪Athere (fatty mush)
▪Skleros (hard)
▪Stages of CAD
A. Early stage/ endothelial damage - silent and goes undetected
B. Fatty streaks
May appears as early as age 15
Increase in surface area as patient ages
Considered _________________ at this stage
Stages of CAD
C. Raised fibrous plaque
Appear in the coronary arteries by age 30
Multi-factor causes
After injury - _______________ develops
Entrapped lipids become calcified
Vessels become narrowed
Stages of CAD
D. Complicated lesions
Most dangerous phase of the disease
Hemorrhages occur when the walls stretch
Layers develop that consist of calcification, lipids, thrombus, dead / necrotic tissue
Necrotic tissue becomes hard and causes _____________ and narrowing
▪CAD Risk Factors
▪Unmodifiable
Age, Gender, Race
Family History
Diabetes (both)
Modifiable
Serum Cholesterol > 200
HTN
Smoking( leads to HTN and endothelial stress)
Drinking (also leads to HTN, empty calories/wt gain)
Obesity (contributes to both HTN and hyperlipidemia) )
Sedentary lifestyle
Stress and behavior patterns
Diabetes (both)
CAD - Health Promotion and Maintenance
Identify those at risk
Eliminate risk factors
Health education
Nutrition (decreased saturated fats, cholesterol; increase in complex carbs, fruits, vegetables)
Meds – chart on page 711
▪drugs that bind with bile acids in the intestine, forming insoluble complexes and
resulting in removal of LDL and cholesterol (Bile Acid Sequestrants)
▪Drugs that resist lipoprotein production (Lopid)
▪Inhibit cholesterol synthesis (ie Lipitor)
▪Inhibit absorption of cholesterol in intestine ( ie Zetia)
▪Know these 4, rest you will learn in Pharm.
CAD - Angina Pectoris
Pathophysiology
Demand for oxygen _______________ the supply
May be due to atherosclerosis
Can occur with arrhythmia
Precipitating factors
physical exertion
strong emotions
extreme temperatures
heavy meals
sexual activity
stimulants such as caffeine
CAD – Angina
Types of Angina
Stable (______________)
Unstable (progressive)
Prinzmetal’s Variant (coronary vasospasm)
▪rare
▪often with hx of migraines or Reynaud’s
▪may occur in patient without CAD
▪can follow period of high physical demand
▪may occur at rest
▪may follow stress/ epinephrine, histamine, prostaglandins
CAD - Angina
Clinical manifestations
chest pain
vague, strange feelings, pressure or ache in the chest
may c/o indigestion or burning
other sites in the body
Complications
____________________
MI
Diagnostic tests
history
lipid panel
treadmill
nuclear imaging
angiography
▪Management of CAD
Nitrates – dilate coronary arteries and peripheral vessels
Chest pain not relieved by rest
Sublingual 5 minutes apart up to 3 (remember 3 x 5min apart)
If no relief, seek medical assistance (911)
Routes of delivery:
Sublingual
Ointment
Transdermal
Long acting
I_______________
Management of CAD
Antiplatelet aggregate
Beta Blockers
Calcium channel blockers
Percutaneous transluminal coronary angioplasty (PTCA)
Atherectomy / laser atherectomy
▪Nursing Management of Acute Condition
▪Assess the etiology of the discomfort
▪Oxygen and nitrate administration
▪Narcotics
▪Vital signs
▪Comfortable positioning
▪ECG
** Chest Pain in ED ..? Not relieved by nitrates…. Need more specific medications/interventions
▪Management of Acute Coronary Syndrome THROMBINS2
▪Thienopyridines
▪Heparin/enoxaparin
▪Renin–angiotensin system blockers
▪Oxygen
▪Morphine
▪Beta blocker
▪Intervention
▪Nitroglycerin
▪Statin/salicylate
