CLASS 24 - HEART DISEASE Flashcards
What is the equation for cardiac output?
HR x SV
What is the purpose of cardiac compensation?
To increase cardiac output.
What are the 4 mechanisms of cardiac compensation? Which system controls each mechanism?
1) go faster (SNS, increased HR)
2) squeeze harder (SNS, increased contractility)
3) fill up more (RAAS, increased preload)
4) carry more stuff (EPO, increased hb, rr, oxygen)
what are the negative effects on the heart due to cardiac compensation mechanisms
1) go faster
2) squeeze harder
3) fill up more
4) carry more stuff
1) go faster - increased workload
2) squeeze harder - hypertrophy
3) fill up more - dilation + stretch
4) carry more stuff - polycythemia
what is cor pulmonale?
hypertrophy of the RV as a result of disease of the lungs or pulmonary blood vessels.
What are the 4 types of cardiac remodelling?
dilation
hypertrophy
cardiomegaly
cardiomyopathy
what are the negative effects of dilation on the heart?
elongated cells w baggy walls
decreased starling response
larger size of heart w slightly thicker walls.
what is hypertrophy?
overgrowth, thick cells, thick walls, smaller cavity
what is cardiomegaly?
a big heart.
what is cardiomyopathy?
disease of all heart muscle (global)
what is cardiac de-compensation?
what does it result in?
heart “failure”
- myocyte loss therefore heart is stiff + weak
- hgher heart tissue oxygen demand in thick + elongated myocytes
- inefficient pumping due to decreased CO
- prone to arrythmias
what causes cardiac hypertrophy? what are the 2 loads that cause cardiac hypertrophy?
increased workload on the heart .
pressure overload + volume overload
what is physiological cardiac hypertrophy?
what is pathological hypertrophy?
when the heart hypertrophies in response to a physiological stimulus such as aerobic exercise or strength training.
when the heart hypertrophies in reponse to a disease process.
what are the effects of pressure overload on the heart? what are some examples of pressure overload?
thicker ventricle wall, reduced chamber volume
examples: hypertension, aortic stenosis, strength training.
what are the effects of volume overload on the heart? what are some exampes of volume overload?
enlarged chamber size, small increase in wall thickness
ex - aortic regurgitation, aerobic training
identify the 9 acute stressors on the heart that immediately result in a decreased CO.
1) Arrythmias
2) Chemotherapy
3) Pregnancy
4) Pulmonary Embolism
5) Ruptured Papillary Muscle
6) Thyrotoxicosis
7) Hypertension Crisis
8) Myocarditis
9) MI
What are the 7 stressors on the heart that lead to the slow developent of long-term heart failure?
1) Ischemic Heart Disease
2) Hypertension
3) DM
4) Pulmonary Disease
5) Valvular Disease; endocarditis
6) Anemia
7) Cardiomyopathy
What is systolic dysfunction?
Heart fails to generate enough force to adequately pump blood, resulting in decreased contractility and SV.
What is diastolic dysfunction?
Reduced ability of ventricles to fill. Can occur due to failure of the myocardium to relax, or due to increased stiffness of the ventricle.
Why do systolic and diastolic dysfunction often occur together?
Which is responsible for the “forward” manifestations of HF? “Backward” manifestations?
bc if the heart can’t fill properly, it also cannot pump adequate blood. A heart that doesn’t pump blood adequately becomes overfilled.
systolic: forward
diastolic: backward
What is the formula for ejection fraction (EF)?
EF = SV / EDV
What are the main tools used to measure EF?
ECHO
MRI
Angiogram
What is the EF used for?
Used to grade function of the ventricles.
What do the following EFs indicate?
- 60% or higher
- 40-59%
- 20-39%
- less than 20%
- 60% or higher: NORMAL
- 40-59%: MILD dysfunction
- 20-39%: MODERATE dysfunction
- less than 20%: SEVERE dysfunction
What is HFrEF?
Heart Failure w Reduced Ejection Fraction
Describe HFrEF in terms of systolic function, EF, and its effects on the heart.
- reduced systolic function
- EF lower than 50%
- unable to overcome SVR
- loss of muscle cells
- decreased contractility
- structural changes
- high afterload
What is HFpEF?
Heart Failure with Preserved Ejection Fraction.
Describe HFpEF.
HF symptoms with EF greater than 50%
component of diastolic HF
“stiff” ventricle, shifts pressure-volume curve
diminished relaxation in early diastole, diminished compliance (stretch) in late diastole
impaired filling during diastole
- high filling pressures
- venous engorgement (transmits backward)
limits CO
decreased activity tolerance
Describe the 6 stages of congestion w right sided heart failure
1) Right ventricle weakens and cannot empty
2) Decreased cardiac output to system
3) Decreased renal blood flow stimulates renin-angiotensin and aldosterone secretion
4) backup of blood into systemic circulation (vena cavae)
5) increased venous pressure results in edema in legs and liver and abdominal organs
6) very high venous pressure causes distended neck vein and cerebral edema
What are the symptoms of congestion due to right sided heart failure in the body?
- JVD
- Fatigue
- Edema
- Weight gain
- Loss of appetite
Describe the 5 steps of congestion w left sided heart failure
1) Left ventricle weakens and cannot empty
2) decreased cardiac output to system
3) Decreased renal blood flow stimulates renin-angiotensin and aldosterone secretion
4) Backup of blood into pulmonary vein
5) High pressure in pulm capillaries leads to pulmonary congestion or edema
what are the symptoms of congestive left sided heart failure in the body?
- fatigue
- paroxysmal nocturnal dyspnea
- chest pain
- SOB, wheezing
- drowsiness
What are the clinical manifestations of heart failure? (THERE ARE LOTS)
- fatigue, activity intolerance
- anxiety, depression
- difficulty concentrating, confusion
- dizziness, fainting, lightheadedness
- drop in BP, orthostatic hypotension, faint pulse
- increased HR, palpitations, heaves, lifts, thrills
- arrhythmia
- anemia or polycythemia
- dyspnea / SOB
- increased WOB
- decreased PaO2 and slight increase in PaCO2
- orthopnea
- paroxysmal nocturnal dyspnea
- pulmonary edema
- dry, hacking cough
- pink, frothy sputum
- angina
- Fluid retention (increased NA, decreased albumin)
- weight gain
- increased JVP, hepatomegaly
- edema in legs, sacrum, ascites
- nocturia, decreased daytime urination
- ascites, nausea, anorexia, GI bloating
- LV thrombus leading to embolism
- renal insufficiency
Describe Class I Heart Failure.
asymptomatic
Describe Class 2 Heart Failure
symptomatic w moderate exertion
Describe Class 3 Heart Failure
symptomacic w minimal exertion
Describe Class 4 Heart Failure
symptomatic at rest
Describe Stage A HF according to to the ACC / AHA
- high risk for HF
- no structural changes
- no symptoms
Describe Stage B HF according to to the ACC / AHA
- structural heart disease changes
- no symptoms
Describe Stage C (AHA / ACC class II and III) HF according to to the ACC / AHA
- structural changes
- past or present symptoms
Describe Stage D HF according to to the ACC / AHA
- advanced structural heart disease w marked symptoms of HF at rest despite maximal medical therapy. Specialized interventions requried.
What is the formula for CO?
What is the formula for BP?
CO = HR x SV BP = (HR x SV) x SVR
What are the 3 main mechanisms used to treat / reduce HF?
- Treat / reduce underlying condition (stressor)
- Exercise training for all stable patients
- Devices to treat HF (ICD, CRT, VAD, Transplant)
In what scenario should ICDs be used?
EF less than 30% due to a high risk of sudden cardiac death
In what scenario should CRTs be used?
low EF
Wide QRS
Identify the 6 drug classes used to treat heart failure.
- diuretics
- RAASi
- beta blockers
- ivabradine
- inotropic agents
- vasodilators
what are the 5 types of RAASi’s used to treat heart failure?
1) Ace Inhibitors
2) Angiotensin Receptor Blockers (ARBs)
3) angiotensin receptor neprilysin inhibitors (ARNIs)
4) aldosterone antagonists (MRAs)
5) Direct Renin Inhibitors
what is the purpose of diuretics to treat HF?
what precautions should be taken?
Provide 3 examples of diuretics and their effect on potassium levels in the body.
- first line for volume overload
- reduce afterload, edema, and cardiac dilation
- precaution: not to over-reduce CO and BP
- furosemide (decreased K)
- hydrochlorothiazide (decreased K)
- spironolactone (increased K)
Provide 4 examples of ACE inhibitors (the “prils”)
captopril
enalopril
ramipril
lisinopril
Describe the function of Ace Inhibitors (ex - captopril, enalopril, ramipril, lisinopril) as well as the risks associated
- first line used to prolong life
- arterial / venous dilation and reduces aldosterone
- increased kinin likely reduces cardiac remodelling
- risks: decreased BP, increased potassium, intractable cough / angioedema
- risk of renal impairment
- start low dose and titrate up as tolerated
Provide 3 examples of ARBs (angiotensin reuptake inhibitors) - the “artans”
valsartan, losartan, candesartan
describe the function of ARBs (valsartan, losartan, candesartan).
similar but not identical to ACE-inhibitors
no increased kinin so less reduced remodelling
typically used if intolerant to ACE-inhibitors
provide an example of an ARNI drug
sacubitril / valsartan (Entresto)
describe the function of ARNIs (encresto)
new, very effective
class II HF, replace ACE-Inhibitors and ARBs
Angiotensin Receptor Neprilysin Inhibitor
Increased natriuretic peprides (ANP, BNP), decreased RAAS
Provide 2 examples of RAASi’s.
1) Aldosterone Antagonists (MRAs)
2) Direct Renin Inhibitors
Provide 2 examples of Aldosterone Antagonists (Mineralcorticoid Receptor Antagonists)
spironolactone
eplerenone
Describe the function of Aldosterone Antagonists (MRAs) -
- add to ACE inhibitors or ARBs for residual adosterone
reduce symptoms of HF, prolong life
block receptors (don’t block production)
risk harmful effects on the heart
increased potassium and renal impairment risk
provide an example of a Direct Renin Inhibitor
aliskiren
what are Direct Renin Inhibitors used for?
only approved for use in HTN. not HF.
Provide 3 examples of beta blockers (the ‘lol’s)
- carvedilol
- bisoprolol
- metoprolol
what is the function of beta blockers (carvedilol, bisoprolol, metoprolol)
- start w low dose and watch for bradycardia
- slows progression of HF, increased Heart Function, prolongs life
what is the function of ivabradine?
used for stable, symptomatic HF w low EF, NSR
May replace BB if contraindicated
Slows HR in nodal cells
provide 3 examples of inotropic agents
digitalis (digoxin)
dopamine
milrinone
describe the function of digitalis (digoxin)
high toxicity
older adults
descibe the function of dopamine
sympathomimetic
provide 2 examples of vasodilators
isosorbide
nitroglycerine
what is the function of isosorbide?
reduce afterload and improve renal perfusion
what is the function of nitroglycerine?
potent venodilator
reduce preload
concern for decreased BP, and increased HR
what drugs should be used to manage stage A heart failure? what other strategies can be used?
goal is to delay / prevent onset of stage B
Use Ace-inhibitors or ARBs
Reduce smoking, alcohol use
exercise has other benefits
what drugs should be used to manage stage B heart failure?
beta blockers w ace inhibitors or ARBs
what drugs should be used to manage stage C heart failure? what other strategies can be used?
goal is to relieve congestive symptoms, improve functional capacity and QOL, slow remodelling, prolong life
diuretic, ACE-Is or ARBs, BBs
Avoid NSAIDs bc they icnrease the toxicity of diuretics and ace inhibitors, avoid antiarrhythmics
what drugs should be used to manage stage D heart failure? what other strategies can be used?
goal is symptom mgmt
BB and ACE-I may cause brady, hypotension, renal failure
end of life palliative care initiated
