Flashcards in Heart Failure I - Pathophysiology (complete) Deck (22)
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1
What is the prevalence of heart failure in the US?
~6,000,000
2
What is the incidence of heart failure in the US?
~550K
3
What is the mortality of heart failure in the US?
~281K
4
What is the cost of heart failure in the US?
>$40 billion
looks like even more prevention efforts are really really needed
5
Why is heart failure so costly in the US? Obviously going for the surface level explanation here. You can have long ass conversations about this
- Highly symptomatic and progressive
- Causes decreased quality of life, hospitalizations, and death
- symptomatic pts: half dead in 5 yrs (more deadly than cancer)
- primarily affects older people (median: 75yrs)
- Incidence/prevalence increasing b/c of aging pop'n and people surviving initial cardiac disease
6
Define the syndrome of heart failure
- describes lots of signs and symptoms caused by many possible abnormalities of heart function
- two types: forward failure, backward failure
7
Describe forward heart failure
- Inability of heart to pump blood forward at a sufficient rate to meet metabolic demands of body
- Overall: POOR forward blood flow
- Decreased CO
8
Describe backward heart failure
- The ability to pump blood only if cardiac filling pressures are abnormally high
- Backward buildup of pressure --- AKA Congestion => ^ filling pressures
- A response to low flow
9
What is systole?
Ventricular contraction
10
What is diastole?
Ventricular relaxation and filling
11
Describe systolic dysfunction
- a problem w/ squeeze => decreased contraction and inotropy
HALLMARKS:
1) Decreased ejection fraction
[e.g. HF w/ reduced EF (HFrEF), LV systolic dysfunction (LVSD)]
2) Ventricular enlargement [e.g. dilated cardiomyopathy (DCM)]
12
What are the causes of systolic dysfunction?
1) direct destruction of heart myocytes (e.g. MI, viral myocarditis, alcohol)
2) Overstressed heart muscle (e.g. tachy-mediated HF, Meth abuse, catecholamine mediated)
3) Volume overloaded heart muscle [e.g. mitral regurgitation, high CO (blood shunting, wet beriberi)]
13
Describe diastolic dysfunction
- a problem with filling => decreased lusitropy and relaxation
HALLMARKS:
1) Normal EF [e.g. HF w/ preserved EF (HFpEF), preserved systolic function (PSF)]
2) Ventricular wall thickening [e.g. LV hypertrophy (LVH), hypertrophic cardiomyopathy (HCM)]
14
What are the causes of diastolic dysfunction?
1) High afterload/pressure overload (e.g. HTN, aortic stenosis, dialysis)
2) Myocardial thickening/fibrosis (e.g. HCM, 1ary restrictive CM)
3) External compression (e.g. pericardial fibrosis/constrictive pericarditis, pericardial effusion)
15
What are the compensatory responses to decreased CO?
1) Neurohormonal activation
2) Frank-Starling increases in preload
3) Ventricular remodeling (hypertrophy & dilation)
16
Describe neurohormonal activation as a compensatory response to decreased CO
- Decreased filling/SV => decreased CO
- Juxtaglomerular apparatus in kidney senses lower flow => activates RAAS
- Causes ^ Na retention, vasoconstriction
- Carotid sinus/aortic baroreceptors sense lower pressure => ANS/adrenergic activation
OVERALL: ^ Na retention + vasoconstriction + ^HR => ^ volume => ^ LV filling
17
Describe Frank-Starling increases in preload as a compensatory response to decreased CO
- ^ LV filling => ^ SV
- SV preserved by increasing end-diastolic filling presure
18
Describe ventricular remodeling as a compensatory response to decreased CO
- Long term cardiac workload & metabolic demand increasing => adverse myocardial remodeling
- Includes ventricular hypertropy/dilation, myocardial damage/apoptosis, myocardial fibrosis
- Overtime remodeling=> decreased contractile force and dynamic function, increased diastolic stiffness
19
Describe right sided HF
- normally: RV pumps same amount of blood as LV --- does this at lower pressures => RV work is less => RV is a thin walled structure
- RV stresses => failure to pump blood to lungs
- Forward RV HF: decreased circulating blood flow
- Backward RV HF: increased venous pressure
20
What are the causes of right-sided HF?
1) Left HF
2) Lung disease/ pulm HTN/ RV pressure overload
3) RV volume overload
4) Damage to RV myocardium
21
Describe left HF as a cause for right-sided HF
- Backward HF from LV dysfunction => stress to right side
- B/c of increasing pulm venous pressure
22
