Heart Failure Pathophysiology

Question 1

what is heart failure

Answer 1

failure of the heart to meet the demands of the body

Question 2

causes of HF

Answer 2

mainly - ischemic heart disease - atherosclerosis, MI - scarring and loss of function

but also - arrhytmia, hypertension, CHD’s, aortic stenosis

Question 3

what is the Ejection fraction

Answer 3

amount of blood ejected

SV/EDV

Question 4

how does HF occur - 3 ways

Answer 4

it can occur due to - reduced preload - from improper filling - ie small chamber, hypertrophied, stiff heart

increase afterload - hypertension ect

reduced myocardial contractilitiy - damaged muscle cant contract proplerly - fibrosed muscle walls or an arrhytmia

Question 5

how do we classify HF

Answer 5

HFrEF - systolic dysfuntion, contractility problem - most common

HFpEF - diastolic dysfunction
fillin problem
same EF but lower total volume

can be LV (common) or RV (pulmonary issue)
Bivernticular - LV will often cause RV failure

Question 6

outline frank starlings curve in HF

Answer 6

the LVEDP increase without the normal gain in CO

increased LV filling - causes pulmonary congestion

Question 7

what does the big CO drop from HF cause

Answer 7

Damaged ventricular tissue
Reduction in efficiency of ventricular contraction
Reduced stroke volume
Reduced cardiacoutput
Neuro-hormonal activation

Drop in CO - drop in BP - Baroreceptors response - incease the SNS - incr HR and TPR - INCR Afterload

drop in CO then BP - activates RAAS - more blood volume, vasoconstricition - incr Afterload and preload

result is a large increase in cardiac work on an already failing heart - give ARB’s , BB’s and ACEi to reduce work load

Question 8

what are the clinical signs and symptoms of heart failure

Answer 8

Symptoms will often include
– Fatigue/ lethargy,
– Breathlessness
– +/- leg swelling

• Many signs (and symptoms) due to increased interstitial fluid (oedema) - higher venous pressure - backs up the capillaries to leak out
– Pulmonary tissues
– Peripheral tissues (dependent areas i.e. lower limbs)

Question 9

sings of RVHF vs LVHF

Answer 9

Left ventricular heart failure 
failure
Fatigue/lethargy
Breathlessness
Orthopnoea 
Paroxysmal nocturnal dyspnoea

Right ventricular heart failure
Fatigue/lethargy 
Breathlessness 
 Peripheral oedema (pitting)
Raised jugular venous pressure