4 Cardiac Failure Flashcards
Give some other names for Cardiac Failure
- Chronic/acute heart failure
- Congestive failure
- Congestive cardiac failure
Define Cardiac Heart Failure
The heart fails when it is unable to eject blood delivered to it by the venous system
- Failure of the heart as a pump to meet circulatory demands
Describe how to distinguish between acute and chronic heart failure
Acute
- Happens now, wasn’t there before, may go away or stay (and become chronic)
Chronic
- Can be improved by medicine, but will be there permanently
Describe one way to distinguish between left/right heart failure + biventricular failure (classification)
To classify
- Left-sided heart failure (LHF) - most common type
- Right-sided heart failure (RHF)
- Bi-ventricular heart failure (LHF + RHF)
- High-output heart failure (least common type)
Describe another way to distinguish between left/right heart failure + biventricular failure (D vs S failure)
Diastolic vs Systolic Heart Failure
Systolic Heart Failure (SHF): problem with the emptying heart
- this is characterised by a low ejection fraction
> EF <45/50%, (Normal is from 55% to 80%)
Diastolic Heart Failure (DHF): problem with filling the heart
- this is characterised by normal EF at rest
- In addition, there is usually S4 (4th sound) atrial gallop,
> (due to increased resistance to filling in late diastole)
- There is an increase in left atrial and left ventricular end-diastolic pressure
Explain how to work out ejection fraction (EF)
EF = Stroke / L Ventricular
Volume End-diastolic Volume
EF = SV / LVEDV
What is ejection fraction?
The L ventricle does not completely empty during systole - this is End-systolic volume (around 50ml)
EDV - ESV = Stroke volume (SV), which defines the amount of blood transferred to the arterial system during systole
> SV should be > 60ml is a healthy person
[SV] / [EDV] = Ejection fraction
- normally, EF is around 55% to 80%
Ejection fraction is an important measure of cardiac efficiency and health,
- therefore is used clinically to assess cardiac status in patients with heart failure
Define and describe Left Ventricular Failure
(LV systolic Failure)
LVSF
LVF is when the LV cannot efficiently eject blood into the aorta
- This is a problem with emptying the heart
- It is the most common systolic failure
- It can cause an increase in the LVEDV (volume) and the LV end-diastolic pressure (LVEDP), due to an increased preload
- Increased LVEDV and LVEDP (i.e. hydrostatic pressure) leads to a backup of blood into the lungs, producing Pulmonary Oedema
Describe a cause for LVF (systolic)
The most common cause is Ischaemia (inadequate blood supply)
- Due to coronary artery atherosclerosis (most common cause)
- Or post-MI
Other rarer causes are:
- Myocarditis
- Dilated cardiomyopathy (thickness of LV is less)
Define and describe Left Ventricular Diastolic Failure
LVDF
LVDF is when there is a non-compliant LV (stiff ventricle) with impaired relaxation.
- It is a problem with filling
Give some causes of LVDF
- Concentric LV hypertrophy due to essential HTN (most common cause)
- AV valve stenosis
- Hypertrophic cardiomyopathy
- Restrictive cardiomyopathy (sarcoid, amyloid)
All these mean the heart can’t fill
If there is HTN:
- hypertrophy means the heart responds by enlarging and needing more muscle to pump more blood (against the increased BP)
- This means there is not as much space in the LV for blood to fill up in
- And the muscle cannot relax as well
Define and describe Right-sided heart Failure
RHF
RHF is when the R Ventricle cannot effectively pump venous blood into the lungs
- (either as it can’t pump, or it can’t fill)
This means:
- Blood pools under pressure in the venous system (blood builds up behind failed heart)
- Increase in R Ventricle afterload (increased resistance to blood flow out of the RV (increased resistance in the pulmonary circulation
Give some causes of RHF
- LHF (most common cause - backlog of blood from LV into the lungs, so there is more pressure in the lungs)
- Pulmonary Hypertension
- Saddle embolus
All these increase RV afterloads
- increased resistance to blood flow out of the RV
List some signs and symptoms of LHF
- Dyspnoea - shortness of breath (Pulmonary Oedema)
- Pulmonary Oedema
- Paroxysmal nocturnal dyspnoea
Describe Pulmonary Oedema as a sign of LHF
Pulmonary oedema
- An increase in the LVEDV leads to an increase in hydrostatic pressure (LVEDP)
- That is transmitted back into the pulmonary capillaries
- Once pulmonary capillary hydrostatic pressure overrides oncotic pressure
- a transudate enters the interstitial space and then into the alveoli, producing pulmonary oedema
Clinical Features:
- This oedema narrows airways + produces an expiratory wheeze (cardiac asthma)
- You can also get bibasilar inspiratory crackles
- Pink frothy sputum is also a feature