Heart Failure I - Pathophysiology (complete)

Question 1

What is the prevalence of heart failure in the US?

Answer 1

~6,000,000

Question 2

What is the incidence of heart failure in the US?

Answer 2

~550K

Question 3

What is the mortality of heart failure in the US?

Answer 3

~281K

Question 4

What is the cost of heart failure in the US?

Answer 4

> $40 billion

looks like even more prevention efforts are really really needed

Question 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

Answer 5

• 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

Question 6

Define the syndrome of heart failure

Answer 6

• describes lots of signs and symptoms caused by many possible abnormalities of heart function
• two types: forward failure, backward failure

Question 7

Describe forward heart failure

Answer 7

• Inability of heart to pump blood forward at a sufficient rate to meet metabolic demands of body
• Overall: POOR forward blood flow
• Decreased CO

Question 8

Describe backward heart failure

Answer 8

• 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

Question 9

What is systole?

Answer 9

Ventricular contraction

Question 10

What is diastole?

Answer 10

Ventricular relaxation and filling

Question 11

Describe systolic dysfunction

Answer 11

• 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)]

Question 12

What are the causes of systolic dysfunction?

Answer 12

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)]

Question 13

Describe diastolic dysfunction

Answer 13

• 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)]

Question 14

What are the causes of diastolic dysfunction?

Answer 14

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)

Question 15

What are the compensatory responses to decreased CO?

Answer 15

1) Neurohormonal activation
2) Frank-Starling increases in preload
3) Ventricular remodeling (hypertrophy & dilation)

Question 16

Describe neurohormonal activation as a compensatory response to decreased CO

Answer 16

• 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

Question 17

Describe Frank-Starling increases in preload as a compensatory response to decreased CO

Answer 17

• ^ LV filling => ^ SV

- SV preserved by increasing end-diastolic filling presure

Question 18

Describe ventricular remodeling as a compensatory response to decreased CO

Answer 18

• 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

Question 19

Describe right sided HF

Answer 19

• 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

Question 20

What are the causes of right-sided HF?

Answer 20

1) Left HF
2) Lung disease/ pulm HTN/ RV pressure overload
3) RV volume overload
4) Damage to RV myocardium

Question 21

Describe left HF as a cause for right-sided HF

Answer 21

• Backward HF from LV dysfunction => stress to right side

- B/c of increasing pulm venous pressure

Question 22

Describe lung disease/ pulm HTN/ RV pressure overload as a cause for right-sided HF

Answer 22

• Cor pulmonale: when 1ary lung disease causes HF

- COPD, 1art pulm HTN, sleep apnea