W3L3 Cardiac Failure Flashcards
What is an example of a condition that causes high output heart failure (ie increased body needs rather than reduced CO)?
Paget’s disease of bone:
Chronic disorder of the skeleton in which areas of bone undergo abnormal turnover, resulting in areas of enlarged and softened bone
In Paget disease, both osteoclasts and osteoblasts become overactive in some areas of bone, and the rate at which bone is broken down and rebuilt in these areas increases.
Heart failure develops because the increased blood flow through the affected bone puts extra stress on the heart.
In systolic dysfunction, is ejection fraction high, low or normal?
low
In diastolic dysfunction, is ejection fraction high, low or normal?
normal
Where is the main pressure drop in the vascular system?
arterioles (capillary pressure almost= venous pressure)
What are starlings forces acting on the vessel and in which direction?
hydrostatic pressure pushing water out of the vessel, osmotic pressure pushing water back into the vessel.
Does increased arterial pressure cause oedema?
No (pressure is decreased by arterioles so it doesn’t reach the capillaries)
Does increased venous pressure cause oedema?
yes
What are the 4 causes of oedema?
Increased venous pressure (HF, fluid overload)
Decreased osmotic pressure (renal or liver failure–> plasma protein loss)
Inflammation (exudate rather than transudate–> increased capillary permeability)
Blocked lymphatics (eg: due to cancer)
What is the cause of oedema in HF?
CO low–> increased ventricular end diastolic pressure to increase CO–> increased atrial pressure–> increased venous pressure.
Needed to keep CO the same in the face of decreased contractility.
What is the mechanism of fluid retention in heart failure?
Decreased CO–> decreased renal blood flow–> sensed by macula densa in JGA–> renin-angiotensin-aldosterone–> fluid and Na retention and K loss–> vasoconstriction and increased BP
What is the mechanism of orthopnea?
lie down–> increased venous return to the heart-> more fluid in pulmonary circulation–> increased hydrostatic pressure causes fluid to leak form capillaries
What are the 7 important causes of heart failure?
- Ischaemic heart disease: myocardial infarct
- Valvular heart disease
- Hypertensive heart disease
- Congenital heart disease
- Cardiomyopathy
- Cor pulmonale (pure right heart failure caused by COPD, pulm fibrosis, cystic fibrosis and VQ mismatch)
- Pericardial disease (tampenade or fibrosis–> heart can’t fill).
Does rapid AF cause HF or is it a cause of HF?
both
Can the JVP be elevated and pulmonary artery pressure be normal? In what circumstances?
yes- core pulminale, PE, right sided structural disease, R venticular cardiomyopathy.
What is the diagnostic criteria for systolic dynfunction HF?
Echocardiography:
40-50%= mild
30-40%= moderate
<30%= severe
