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
Describe Paroxysmal nocturnal dyspnoea as a symptom of LHF
Dyspnoea at night when the patient is lying flat
- Without the effect of gravity, fluid from the interstitial space moves into the vascular compartment
- This increases venous return to the R side of the heart + then to the failed left side of the heart,
- thus leading to pulmonary oedema
This can be relieved by standing or placing pillows under the head
(no. of pillow = symptomatic relief can be quantitated)
Describe what you could see on an X-ray of a patient with LHF
- Congestion in the upper lobes (early finding)
- Perihilar congestion (bat-wing configuration)
- Fluffy alveolar infiltrates
- Kerley lines (septal oedema)
Chest X-ray can also be used to track/monitor the patient’s response to therapy
Describe what can be found on a clinical examination of a patient with LHF (precordium)
Left-sided S3 (sound)
- can be normal in young people.
- though to be due to a sudden rush of blood entering a volume overloaded left/right ventricle
S4 heart sound
- pathological
Name a blood test that can be done when testing a patient for LHF
BNP
- Brain natriuretic peptic
Describe BNP, its roles and significance in maintaining BP
BNP is brain natiuretic peptic
- A cardiac neurohormone secreted from the ventricles (and brain) when they are volume overloaded
- And in response to Sympathetic NS activation
Natriuretic peptides are involved in the long-term regulation of sodium and water balance, blood volume and arterial pressure:
- Vasodilation (of veins - this reduces venous return + ventricular preload + arteries reduce total peripheral resistance) - this most likely reduces NA release from SNS
- Renal effect - leading to natriuresis (loss of Na+ and water) and Diuresis (affects renin)
Describe why BNP is a useful diagnostic tool (blood test - investigative tool)
BNP is useful in diagnosing LHF
- in LHF, BNP is often elevated/increased
- (normal is < 100pg/ml)
They can:
- predict survival (remains high - bad prognostic sign)
- serum atrial natriuretic peptide (ANP) is also increased in LHF because of L atrial dilation (less useful as a marker)
Describe some signs and symptoms of RHF
The RV cannot effectively pump venous blood into the lungs.
- Blood pools under pressure in the venous system (blood builds up behind the failed heart)
Right-Sided HF signs and symptoms:
- Increased volume in venous system (lot of symptoms)
- Prominence of internal jugular veins (JVP is raised - column of blood in neck backlogs)
- Functional TV (tricuspid valve) regurgitation - blood goes the wrong way
(stretching of the TV ring from RV volume overload)
- Right-sided (louder in) S3 and S4 heart sounds - same reasons
- Backlog to liver - painful hepatomegaly (liver enzymes will be raised)
- Backlog to limbs = dependent pitting oedema - due to increased venous hydrostatic pressure
- Cyanosis - increased time available for peripheral tissue to extract O2, which decreases O2 saturation
> this is enough to produce cyanosis (bluing of blood)
Describe things that make pre-existing heart failure worse
- Non-adherence to medical management
- Excess water (fluid restriction is < 2L/day)
- Excess sodium (causes movement of water into vascular spaces)
State some humoral factors involved in the neurohormonal adaptation
(describe this first)
Neuro - activation of sympathetic NS
Hormonal - RAAS, ADH, Atrial Natriuretic Peptide (ANP)
These ‘neurohormonal’ systems induce a number of changes in the heart, kidneys, and vasculature that are designed to maintain cardiovascular homeostasis
Describe the role of the Sympathetic NS in neurohormonal adaptation (as a humoral factor)
- One of the most important neurohormonal adaptations in heart failure is the activation of the SNS, which occurs very early in the course of the disease
- There are increased circulating levels of the androgenic neurotransmitter ME secondary to increased SNS signalling and NA release from adrenergic nerves with subsequent ‘spill over’ into the plasma, as well as reduced uptake by adrenergic nerve endings
Describe the role of renal function in Neurohormonal adaptation (as a humoral factor)
Hallmarks of worsening heart failure:
- Increasing salt and water retention by the kidneys
- leading to pulmonary and peripheral oedema
This oedematous state is not the result of intrinsic renal dysfunction but rather an orchestrated response to increased SNS traffic to the kidney
- Increased sympathetic activity leads to peripheral vasoconstriction of the afferent renal artery
- and decreased blood flow to the juxtaglomerular apparatus in the kidney,
- with the resultant release of Renin into the afferent arteriole by the Juxta. apparatus
Describe how a diagnosis of chronic heart failure may be made
- Suspect heart failure in patients with the features previously discussed
> (signs and symptoms - dyspnoea, PE, paroxysmal nocturnal dyspnoea) - Take into account the patient’s history + examination
Describe some tests that can be done when investigating heart failure in a patient
(or to support a diagnosis)
- Measure their N-terminal pro-B type natriuretic peptide level
- Arrange a 12-lead ECG
> most common finding is LV hypertrophy (tall T waves) - Transthoracic Echocardiogram
> will show whether HF is diastolic or systolic failure - Chest X-ray
(look for signs of congestion, PE etc.)
Describe the treatment goals of chronic heart failure
- Treat the underlying cause of heart failure (acute/chronic)
Common:
- symptomatic relief, avoid exasperating factors
