Heart Failure I - Pathophysiology (complete) Flashcards
What is the prevalence of heart failure in the US?
~6,000,000
What is the incidence of heart failure in the US?
~550K
What is the mortality of heart failure in the US?
~281K
What is the cost of heart failure in the US?
> $40 billion
looks like even more prevention efforts are really really needed
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
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
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
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
What is systole?
Ventricular contraction
What is diastole?
Ventricular relaxation and filling
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)]
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)]
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)]
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)
What are the compensatory responses to decreased CO?
1) Neurohormonal activation
2) Frank-Starling increases in preload
3) Ventricular remodeling (hypertrophy & dilation)
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
Describe Frank-Starling increases in preload as a compensatory response to decreased CO
- ^ LV filling => ^ SV
- SV preserved by increasing end-diastolic filling presure
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
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
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
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
Describe lung disease/ pulm HTN/ RV pressure overload as a cause for right-sided HF
- Cor pulmonale: when 1ary lung disease causes HF
- COPD, 1art pulm HTN, sleep apnea
