Week 9 Flashcards by Avaline Duguay

What is heart failure?

any functional of structure issue of the heart that causes low cardiac output
left and/or right sided heart failure
acute or chronic

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Describe chronic heart failure

long term condition (months/years) → ventricle undergoes adaptive responses (hypertrophy, dilation)
eventually the supply can no longer keep up with demand (heart has weakened & can no longer maintain required cardiac output)

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What are the causes of chronic heart failure?

any pathology that affects regular heart function
→ coronary artery disease, previous MI
→ chronic uncontrolled hypertension
→ others: incompetent or stenosed heart valve, infection/inflammation of heart, arrhythmias

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HR is modulated by ___ or ____

SNS (+ chronotropy) or PNS (- chronotropy)

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SV is a function of…..

preload and myocardial contractility

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What is the frank-starling law?

the length tension relationship of cardiac myocytes - shows relationship between preload (EDV) and stroke volume

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What is the ejection fraction?

how well the ventricles pump blood with each beat
EF = (SV/EDV) x 100
normal = 55-70%

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Heart failure can be due to which two types of dysfunction?

systolic dysfunction and/or diastolic dysfunction

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What is systolic dysfunction?

ventricles can’t pump hard enough during systole (contractility is impaired)
→ due to weakened ventricle
→ result: lower ejection, lower CO
impaired contractility → increased ESV → decreased SV → decreased cardiac output

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What is diastolic dysfunction?

not enough blood fills into ventricles during diastole
→ due to impaired relaxation of the ventricle
→ result: normal ejection fraction, lower CO
- decreased EDV → decreased SV → decreased CO

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Systolic dysfunction = HFrEF. What does this mean?

heart failure with reduced EF

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Diastolic dysfunction = HFpEF. What does this mean?

heart failure with preserved EF

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During the initial compensation to attempt to restore cardiac output, multiple mechanism attempt to maintain sufficient __________ & __________ in order to perfuse tissues

cardiac output and mean arterial pressure

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What is the one physiological type of ventricular hypertrophy? two pathologic?

physiological: symmetric hypertrophy
pathologic:
- concentric
- eccentric

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What is symmetric hypertrophy?

proportionate increase in wall thickness and diameter
healthy muscle fiber growth

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What is concentric hypertrophy?

disproportionate increase in wall thickness
myofibrils grow in parallel → thicker muscle fibers
pressure overload

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What is eccentric hypertrophy?

disproportionate increase in wall circumference
myofibrils grow in series
longer muscle fibers

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Eventual decompensation leads to congestive heart failure. What does this mean?

CO eventually decreases → decreased myocardial tissue function
ejection fraction reduced
→ EDV increased because ventricle output is less than inflow of blood
→ blood begins to back up into pulmonary or systemic circulation (depending on the side of heart that is failing)

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Describe the steps leading to left-sided heart failure

e.g. hypertension (or MI, aortic valve stenosis) → LV must contract with more force to overcome afterload → LV hypertrophy → eventual failure: decreased CO, blood backs up into pulmonary circulation leading to pulmonary congestion or edema

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Describe the steps leading to right-sided heart failure

e.g. pulmonary disease (like COPD) → increased resistance in pulmonary capillaries → increased RV workload → RV hypertrophy & dilation and eventual failure (cor pulmonale) → blood backs up into systemic circulation → congestion → leading to e.g. edema below heart

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What is a stroke?

a cardiovascular disorder with neurological consequences
- an area of the brain is deprived of blood
- symptoms depend on area deprived of blood

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What are the two types of strokes?

ischemic (85%) and hemorrhagic (15%)

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What is an ischemic stroke?

blood flow to an area of the brain is blocked off
extent of damage depends on length & degree of blockage
→ partial vs total occlusion
→ ~5 min of ischemia → irreversible damage to nerve cells → necrosis and inflammation

What are the causes of an ischemic stroke?

atherosclerotic plaque build up in e.g carotid artery → leads to blockage
blood clot that travels to the brain from e.g. athersclerotic progression or other location

What is the treatment for ischemic strokes?

acutre treatment is thrombolytic therapy: TPA-tissue plasiminogen activator: a clot bursting agent. Tight time window for effectiveness

What is a hemorrhagic stroke?

- a burst blood vessel leads to bleeding in an area of brain, causing local swelling & damage - most common cause: severe hypertension - symptoms are severe - extreme headache, loss of consciousness, coma, death - anti-clotting treatment would be life threatening in this case

What is a transient ischemic attack?

- "mini or silent stroke" - temporary blockage of a cerebral artery that resolved - symptoms the same as stroke but can be milder & will fully resolve within 24 hours (even within mins in some cases) without treatment - can be warning signs of impending stroke

What are the risk factors for stroke?

- age - athersclerosis - hypertension - atrial fibrillation

What are the treatments for stroke?

- antithrombotic therapy (if appropriate) - Ots, PTs, speech language pathologist

What is the prevention for stroke?

- reduce risk factors - healthy lifestyle modification - prophylactic treatments

What is the BEFAST response to a stroke?

balance, eyes, face, arms, speech, time

What is the upper respiratory tract?

nasal cavity → larynx

What is the lower respiratory tract?

trachea → alveoli

What is the passage of airflow?

nasal cavity → pharynx → larynx → trachea → primary bronchi (right/left) → many smaller bronchi → bronchioles → alveoli

The bronchioles are the site of...

variable resistance through bronchoconstriction and bronchodilation

The alveoli is the site of...

gas exchange

Air flow depends on....

pressure gradient & resistance

What is bronchodilation? How does it occur?

decreased resistance to airflow - paracrine response: increased PCO2 → relaxation of bronchiole smooth muscle - SNS response: epinephrine binds to β2-adrenergic receptors → relaxation of bronchiole smooth muscle

What is bronchoconstriction? How does it occur?

increased resistance to airflow - paracrine response: histamine released by local mast cells in an immune response - PNS response: ACh binds yo muscarinic receptors → constriction of bronchiole smooth muscle

What is lung compliance?

how easily the lung can expand (△V/△P)

What is lung elastance?

ability of lung to spring back after being stretched. - Inverse of compliance - due to prescence of elastin fibers throughout the lung interstitial space

____ compliance allows lungs to move outward with little force required

high

elastic recoil of the lungs creates an _______ pull

inward

What is radial traction?

- healthy lung tissue contains elastic fibers surrounding alveoli - these elastic fibers pull on the airway bronchioles, helping them open during inspiration (radial traction) - also helps prevent airway collapse during expiration

What factors affect alveolar gas exchange?

O2 reaching the alveoli (composition of inspired air & alveolar ventilation) Gas diffusion between alveoli and blood (surface area & diffusion distance) Adequate perfusion of alveoli

What are the three categories of conditions affecting ventilation or gas exchange?

obstructive lung disease restrictive lung disease cardiovascular disorders

What are obstructive lung diseases?

- airway obstruction causes increased resistance to airflow - larger impact on expiration → gas gets trapped → limited ventilation - e.g. asthma, bronchitis, emphysema, chronic obstructive pulmonary disorder

What are restrictive lung diseases?

- reduced lung compliance → increased stiffness → limited expansion → limited ventilation - near normal rates of inspiration and expiration - eg. pulmonary fibrosis

What are examples of cardiovascular disease that affect ventilation of gas exchange?

- pulmonary edema - pulmonary embolism

In Asthma, bronchoconstriction along with overproduction of mucus in the airways reduces the amount of O2 that reaches the Alveoli. This impacts diffusion rate of O2 due to modification of...

pressure gradient of gases

During left-sided heart failure, blood backs up into pulmonary circulation, raising the hydrostatic pressure and forcing fluid out into the interstitial space. This leads to pulmonary edema. This impacts diffusion rate of gases due to modification of...

Barrier thickness

Which type of lung disease leads to an increase in residual volume due to air trapping?

obstructive lung disease

Which type of lung disease displays a more normal flow rate but an inability to fully inflate lung?

restricitive lung disease

What is a normal FEVI/FVC? Obstructive? Restrictive?

normal: 0.8 Obstructive: =< 0.7 Restrictive: => 0.8

TLC of obstructive lung disease?

= of higher (due to increased residual volume)

TLC of restructive lung disease?

lower (due to decreased IRV, ERV, and RV)