Shock & Heart Failure Flashcards
3 types of shock.
Hypovolemic
Distributive
Cardiogenic
What is hypovolemic shock? Distributive? Cardiogenic?
Hypovolemic - decrease in blood volume due to blood loss via hemorrhage, fluid loss due to endothelial damage, secretions, dehydration
Distributive - vasodilation due to sepsis/toxic shock
Cardiogenic shock - inadequate filling of the arteries caused by cardiac pump failure (ie MI, valve rupture, pulmonary emboli, myocarditis, pericardial tamponade)
What is vasovagal syncope usually caused by which type of shock?
Distributive shock; systemic vasodilation leads to decrease in HR, BP, and ultimately flow to the brain –> fainting
What are the immediate consequences of shock? long-term consequences?
immediate: decrease in BP
long-term: poor tissue perfusion
What are the immediate consequences of heart failure? long-term consequences?
immediate: impaired pump performance
long-term: progressive deterioration of the heart/death of myocardial cells
What is ESPVR a measure of? EDPVR?
ESPVR: measure of ventricular stiffness at the end of systole, measure of ionotropy and contractility
EDPVR: measure of ventricular stiffness at the end of diastole; measure of lusitropy and relaxation
How is ejection fraction calculated?
EF = SV/EDV
What is heart failure?
How does heart failure precipitate itself?
Heart failure: malfunctioning ventricular filling/ejection of blood
Precipitation: cyclical Impaired ejection (systolic heart failure) impaired/reduced filling (diastolic heart failure)
What is the pathophysiology of R heart failure? How is ejection fraction affected?
What is it also known as?
blood backs up and accumulates behind the heart (increased venous pressure) AND too little blood flows into pulmonary circulation
Ejection fraction is not affected
aka backward failure, diastolic HF
What is the pathophysiology of L heart failure? What is it also known as?
too little blood flows into the systemic circulation/out of the heart AND flow backs up into pulmonary veins
Ejection fraction is reduced
aka forward failure, systolic HF
How is EF affected in systolic vs diastolic HF?
Systolic = impaired EF (HFrEF; r = reduced)
Diastolic = Preserved EF (HFpEF; p = preserved)
What are the causes of R heart failure? L heart failure?
RHF: failure of previous contraction to fully pump out all of the blood (ie due to COPD, pulmonary hypertension, congenital heart dz)
LHF: heart can’t generate enough pressure to pump blood out (ie due to ischemic heart disease, hypertensive heart disease, cardiomyopathies, valvular disease)
What are the clinical manifestations of R heart failure? L heart failure?
RHF: JVP, peripheral edema, anasarca (fluid in body cavity), dropsy/edema
LHF: rales, dyspnea, orthopena (dyspnea in supine), PND, fatigue
What are the structural manifestations of R heart failure? L heart failure?
RHF: concentric hypertrophy; EF is normal
LHF: eccentric hypertrophy; EF is low because the EDV is really high
What are the two types of neurohumoral responses?
functional - short term responses that modify the function of existing structures
proliferative - long-term responses that modify cell size, shape, composition, survival
What are the short term responses of neurohumoral signaling on:
cardiac stimulation?
vasoconstriction?
transcriptional activation?
What are the long-term responses of neurohumoral signaling on these 3 parameters?
Cardiac stimulation:
short-term (ie NE) changes HR, contractility, to modulate CO.
long-term - arrhythmias, increased energy demand, which can lead to cardiac myocyte death.
vasoconstriction
short-term: (ie NE) changes afterload to maintain BP
long-term: decrease CO, increased energy demand, which can lead to cardiac myocyte death.
Transcriptional activation
short-term: sarcomeres added to normalize wall stress and maintain CO
long-term: hypertrophy, remodeling; increased energy demand, which can lead to cardiac myocyte death.
What role does the neurohumoral responses play in exercise?
cardiac stimulation + select vasoconstriction to maintain BP, CO, and redistribute blood
What role does the neurohumoral responses play in shock? What does chronic neurohumoral responses result in?
cardiac stimulation + vasoconstriction + salt/h2o retention to maintain perfusion, CO, redistribute blood to vital organs.
BUT
chronic a1 –> decrease CO due to increased afterload
chronic b1 –> arrhythmias
chronic ADH –> kidney damage
What role does the neurohumoral responses play in heart failure?
What do chronic neurohumoral responses result in?
Roles of neurohumoral responses:
maintain circulation
vasoconstriction - maintain afterload/BP
cardiac stimulation - increase HR/contractility
fluid retention - increase preload
proliferative signaling: reduces wall stress
Bad: all of these processes increase energy expenditure + increases energy starvation
How are proliferative signaling good? bad?
increases the # of sarcomeres to normalize wall stress such that CO can be maintained, but long-term signaling can result in an increase in energy starvation, fetal gene expression, remodeling, and ultimately apoptosis.
What hypertrophic phenotype does aortic insufficiency manifest as? aortic stenosis?
AI: eccentric (due to increased diastolic stress)
AS: concentric (due to increase systolic stress - not to be confused with increased systolic HF)
What hypertrophic phenotype does a low EDV manifest as? high EDV?
low EDV: concentric
high EDV: eccentric
What hypertrophic phenotype does ischemic/MI cardiomyopathy manifest as? hypertensive heart disease?
Ischemia/MI: eccentric
hypertensive heart disease: concentric
What hypertrophic phenotype does endurance training cause? strength straining?
Endurance: eccentric
strength: eccentric, but with slightly thicker walls
What’s the difference between physiological and pathological?
Physiological: no tendency for progressive deterioration and myocyte death. Expression of ADULT phenotype genes
Pathological: tendency for progressive deterioration and myocyte death. Expression of fetal phenotype.
Systolic HF leads to:
Diastolic HF leads to:
Systolic HF: progressive dilation/remodeling
Diastolic HF: leads to concentric/increased risk of ischemia
What signaling molecule is involved in eccentric hypertrophy?
concentric hypertrophy?
eccentric: Erk 5
concentric: Erk 1,2
What is the recommended treatment for RHF? LHF?
RHF: diuretics - to decrease preload
LHF: Ace inhibitors, nitrates, b-blockers, aldosterone blockers
Why do drugs that improve survival in systolic HF (eccentric) have less benefit than diastolic HF?
because diastolic HF rarely remodels
What drugs inhibit remodeling?
ACE inhibitors and b-blockers
