Heart Failure Flashcards
What are the 3 mechanisms by which SOB can arise?
Not enough oxygen reaching the lungs:
due to breathing issues, such as asthma + COPD
Not enough oxygen getting into the blood:
this is due to V/Q mismatch - e.g. PE or pulmonary fibrosis
Not enough oxygen reaching tissues of the body:
this is due to issues with the heart - it is not pumping oxygenated blood sufficiently
^ also anaemia + shock
What is cardiac output?
the volume of blood pumped by the heart in one minute
What is the definition of heart failure?
the failure of the heart to maintain the cardiac output (CO) required to meet the body’s metabolic demands
not enough oxygen reaches the rest of the body
CO is RELATIVE to the body’s metabolic demands
CO can be normal, the demands of the body just increased, and this is still HF
What are the 3 ways to classify heart failure?
- acute or chronic
- left or right
- high output state or low output state
What is meant by chronic HF?
a long-term condition in which the heart fails to maintain an adequate CO for the needs of the body
What is meant by acute heart failure?
What are the 2 causes?
rapid onset of the symptoms / signs of HF that requires urgent management
- can be caused by acute coronary syndrome
- OR decompensation of chronic HF
ACS - e.g. heart attach damages the heart and causes it to fail
decompensation - patient has chronic HF that suddenly gets worse due to an exacerbating factor
What is the main difference between acute and chronic HF?
- signs / symptoms are similar, but differ in severity
- investigations are similar
- management is DIFFERENT - acute HF is a medical emergency
What is congestive heart failure and how does it usually occur?
CHF = RHF + LHF
- often a patient has LHF before the pressure backs up into the pulmonary circulation and then into the right heart
if you see the symptoms / signs of RHF, this DOES NOT mean that the person doesn’t also have LHF
What is meant by low output state HF?
this occurs when the heart fails to pump in response to normal exertion
the cardiac output (CO) is reduced
What is meant by high output state HF?
the cardiac output (CO) is normal, but the metabolic demands of the body have increased
the CO is insufficient to meet the increased metabolic demands
e.g. hyperthyroidism, pregnancy, anaemia
What are the 3 categories of causes of chronic LHF?
Valvular:
the aortic and mitral valves are present on the left
Muscular:
when the muscles are weakened / damaged, the heart cannot pump efficiently, reducing CO
Systemic
What are the valvular causes of LHF?
- aortic stenosis
- aortic regurgitation
- mitral regurgitation
What are the muscular causes of LHF?
- ischaemic heart disease (IHD)
- cardiomyopathy
- myocarditis
- arrhythmias (AF)
What are the systemic causes of LHF?
- hypertension
- amyloidosis
- drugs (e.g. cocaine, chemo)
HTN - left heart pumps into the systemic circulation, so if pressure is increased, pressure in the aorta is also increased
this increases the afterload, which backs up into the LH to cause HF
What are the 2 categories of causes of chronic RHF?
- lung-related causes
- valvular causes
ALSO LHF that leads to RHF = congestive HF
What are the lung-related causes of RHF?
- pulmonary hypertension (cor pulmonale)
- pulmonary embolism
- chronic lung disease (e.g. interstitial LD, cystic fibrosis)
the RH pumps into the pulmonary artery, so when the pressure is increased, this backs up into the RH
What are the valvular causes of RHF?
- tricuspid regurgitation
- pulmonary valve disease
What mnemonic can be used to remember that conditions that cause high output HF?
NAP MEALS
N - nutritional (B1 / thiamine deficiency)
A - anaemia
P - pregnancy
M - malignancy
E - endocrine
A - AV malformations
L - liver cirrhosis
S - sepsis
the strain on the heart is greater as these conditions require a greater CO
What are the 3 most common causes of high output HF and why does this occur?
Pregnancy:
due to the metabolic demands of a second person
Anaemia:
the blood isn’t carrying enough oxygen, so the heart needs to compensate + pump harder
Hyperthyroidism:
* there is a high BMR meaning increased metabolic demands
In general, what are the symptoms of LHF and RHF caused by?
LHF:
* LH receives blood from the pulmonary circulation
- blood congesting backwards leads to pulmonary oedema + SOB
RHF:
* RH receives blood from the systemic circulation
- blood congesting backwards leads to peripheral swelling + oedema
think - “what happens if fluid is congested backwards?”
What are the respiratory symptoms associated with LHF?
Dyspnoea:
- paroxysmal nocturnal dyspnoea (PND)
- exertional dyspnoea
- orthopnoea
Other symptoms:
- nocturnal cough
- +/- pink frothy sputum
- general fatigue
What questions can be used to assess SOB, PND and orthopnoea?
SOB:
* how far can you walk without getting breathless?
* how many flights of stairs can you climb?
orthopnoea:
* have you noticed anything that makes SOB worse?
* how many pillows do you sleep with at night? has this changed recently?
PND:
* do you ever wake up at night gasping for air?
How can the signs of LHF be divided?
Heart signs:
* these are signs of whatever is causing the HF
Lung signs:
* these are signs that result from the HF
What are the heart signs associated with LHF?
- raised HR + RR
- irregularly irregular heartbeat
- pulsus alternans
- displaced apex beat
- S3 gallop rhythm
- S4 in severe HF
- murmur (AS, MR or AR)
What is pulsus alternans?
Why does this usually occur in HF + what is it associated with?
- arterial pulse waveform showing alternating strong and weak beats
- it is due to decreased ventricular performance
- occurs when HF is due to resistance to LV ejection - HTN, aortic stenosis, coronary atherosclerosis
it is often associated with an S3 gallop rhythm
What is the S3 gallop rhythm and why does it occur?
- it is the “third heart sound”
- it occurs just after S2 when the mitral valve opens + blood enters the LV
- it is caused by large volumes of blood hitting a very compliant LV
Why might S3 occur in HF patients?
When is it normal?
- it is a sign of an overly compliant LV
- the myocardium is often dilated and overly compliant in HF
it can be normal in young people, athletes and pregnant women
What is the S4 heart sound and why does it occur?
- the “atrial gallop” which is nearly always abnormal
- it occurs when blood strikes a LV that is non-compliant
- atrial contraction forces blood through the AV valves
- it occurs in severe HF where there is LV hypertrophy preventing relaxation of the LV
In general, what type of conditions produce an S3 and S4 heart sound?
- S3 is produced by any condition creating an overly compliant LV
- S4 is produced by any condition creating a noncompliant LV
What are the symptoms of RHF?
- fatigue
- reduced exercise tolerance
- anorexia
- nausea
- nocturia (due to fluid retention)
symptoms (ext nocturia) are more non-specific and it is more about signs
What are the signs associated with RHF?
- swelling of the face
- raised JVP
- TR murmur, raised HR + RR
- ascites / hepatomegaly
- ankle oedema
- sacral pitting oedema
all the signs relate to peripheral swelling
What bedside investigations are performed for HF?
ECG:
* to rule out MI due to SOB
What blood tests are performed in HF and why?
- FBC - to rule out anaemia causing SOB
- U&Es
- LFTs
- TFTs - to rule out hyperthyroidism
- !!! BNP !!!
What imaging might be performed in HF and why?
- CXR - if patient has signs of concurrent pulmonary oedema
- transthoracic echocardiography (TTE)
TTE is the gold-standard for diagnosing HF
imaging is only performed if directed to do so by the blood results
How can levels of BNP be used to direct HF investigations?
BNP is sensitive, but not specific
- if BNP is low, then HF is unlikely
- if BNP is high, a TTE is required to confirm diagnosis
it is sensitive as it is released every time the heart muscle stretches (which occurs in HF)
it is NOT specific as many other heart conditions can cause raised BNP
What is the diagnostic test for HF?
transthoracic echocardiogram (TTE) coupled with doppler
Doppler allows for visualisation of the blood flow in the heart
What 2 parameters can be visualised / calculated using TTE with Doppler?
Structure / function of heart:
visualising this may show the cause of HF
Calculating ejection fraction:
* this is the % of blood present in the LV that is pumped during systole
* a normal value is 50-70%
What is meant by heart failure with reduced EF (HFrEF)?
Why does this occur?
- occurs when EF is < 40%
- this indicates an inability of the ventricle to contract normally, causing HF
previously called systolic HF
What is heart failure with preserved EF?
Why does this occur?
- occurs when EF > 50%
- it indicates an inability of the ventricle to relax and fill normally
previously called diastolic HF
Why might a CXR be performed in HF?
to assess for pulmonary oedema if a patient is breathless
What are the characteristic features of HF on a CXR?
ABCDE:
A - alveolar oedema
B - Kerley B lines
C - cardiomegaly
D - dilated upper lobe vessels
E - effusion
the effusion is a transudative pleural effusion
How can a diagnosis of HF be made without investigations?
a clinical diagnosis can be made using the Framingham criteria
requires 2 majors or 1 major + 2 minors
What are the 4 stages in the management of chronic HF?
- treat the underlying cause - to prevent worsening of the damage
- treat exacerbating factors - to relieve symptoms
- lifestyle modifications
- drugs (ABD)
chronic HF can’t be “cured” so tx aims at prolonging life + alleviating symptoms
What are the 3 main drugs given to chronic HF patients and why?
ACE inhibitors:
given to all patients with LV dysfunction to reduce BP
(enalapril, perindopril, ramipril)
Beta-blockers:
to reduce the O2 demand on the heart
(bisoprolol, carvedilol)
Diuretics:
use if evidence of fluid retention
(loop diuretics - furosemide
or K+ sparing - spironolactone)
Why might a HF patient be given an ARB?
if the ACEi is not tolerated as it can produce a cough
What additional medications are sometimes used in HF?
Hydralazine + nitrates:
considered in Afro-Caribbean patients
Digoxin:
improves symptoms, but not mortality
cardiac resynchronisation therapy:
aims to improve timings of contraction of atria + ventricles
What are the 5 steps involved in treatment of acute HF?
- sit the patient upright
- give 60-100% oxygen
- IV diamorphine 2.5-5mg
- GTN infusion
- IV furosemide 40-80mg
it is a MEDICAL EMERGENCY - so ABC procedure must be performed first
What mnemonic can be used to remember the stages of acute HF management?
DMONS
D - diuretics
M - morphine
O - oxygen
N - nitrates
S - sit-up
(not in correct order)
What is the prognosis of HF like?
- it has a very poor prognosis that is worse than most cancers
- 50% severe HF patients die within 2 years
