HF Pathophysiology

Question 1

Define HF

Answer 1

Affected ability of the ventricle to fill with or pump out blood

Heart fails to pump enough blood to meet the body’s metabolic demands
- affect the whole body

Question 2

Classification

Focus on ventricle

Answer 2

Left ventricular dysfunction
• reduced LV ejection fraction
• preserved LV Ejection fraction

Right ventricular dysfunction

Question 3

Movement of blood via ❤️

Answer 3

from body enter via SUPER VENA CAVA
RA - tricuspid valve - RV - pulmonary artery (to lungs get O2)

From lungs (oxygenated blood)
LA - bicuspid valve - LV - Aorta ( to body)

Question 4

LV dysfunction
types
effect

Answer 4

Types
•reduced EF - systolic dysfunction (HF-LVSD)
• preserved EF - diastolic dysfunction (HF-LVDD)

Effect
Stroke vol ⬇️ ->less in body

Question 5

Systole vs diastole

Answer 5

Contraction vs relaxation

Pump out vs filling

Question 6

Ejection fraction

Answer 6

Proprotion of blood in the V pumped our at each contraction

Amount pumped out after each filling

Question 7

Reduced EF (systolic dysfunction) 
-most common

Answer 7

Enlarged, weakened ventricle -> pump out less than 40-50% ⬇️EF

Failing to pump due to - decreased myocardial contractility
(Impaired squeezing during systole)

Due to:
• coronary artery disease (ischemic- oxy sup decrease to part of heart , which turns hard = hard to contract -> HF)
•systemic arterial hypertension
•valvular heart disease

Question 8

Preserved EF (diastolic dysfunction)

Answer 8

Stiff V (not able to expand much) fill less blood

Failing to pump due to - decreased ability of V to relax : •impaired filling • end diastolic vol⬇️ • increased diastolic LV stiffness

Contractility NOT impaired

Due to:
• coronary artery disease
• long-standing hypertension

Question 9

Pattern of HFrEF

Condition of VOL overload

Answer 9

Vol overload
Increased diastolic pressure (to fill more)
Increased diastolic wall stress
Chamber enlargement
Vol overload

Question 10

Pattern of HFpEF

Condition of PRESSURE overload

Answer 10

P overload
Increased systolic pressure (to pump more)
Increased systolic wall stress
Wall thickening 
Less space 
P overload

Question 11

Right V dysfunction

Lung related

Answer 11

Right V fails to pump effectively
Has to work harder to pump blood to lungs

Due to
-pulmonary hypertension secondary to lung disease

May also due to

• LVDysfunction
• tricuspid valvular disease
• congenital heart disease
• ischaemic affecting rv

Question 12

Pulmonary hypertension leads to remodelling of right side ❤️

Answer 12

Constricted blood vessels in lungs (as fibrosis occur surrounding the vessel)

Weakened RV - as constantly work heard to push blood to ‘Pressured’ areas in lung

Question 13

Compensatory mechanism

• good in short term (while heart work harder

-bad in long term
(Use drug to stop compensation)

Answer 13

• increased sympathetic tone (⬆️heart rate)
• activation of renin angiotension aldosterone system
• sodium and water retention (⬆️stoke vol)
• other neurohormonal adaptations
• cardiac remodelling

Question 14

Neurohormonal cardiac compensation

SNS , RAAS

Answer 14

SNS and RAAS activates each other

SNS:

• vasoconstriction
• heart rate ⬆️
• contractility ⬆️
• RAAS activity ⬆️

RAAS

• vasoconstriction
• BP, aldosterone ⬆️
• fibrosis ⬆️( irreversible)
• Sympathetic tone ⬆️

Question 15

Cardiac remodelling

Answer 15

Progression of disease

Cardiac Dilation

• seen in systolic dysfunction (thinning and weakening of wall)
• ventricles fail to pump adequate amount
• blood accumulate in V , myocardial fibres stretched and V become dilated

Cardiac hypertrophy
- muscle mass and wall thickness ⬆️