Heart Failure Flashcards
What is heart failure?
“A clinical syndrome comprising of dyspnoea, fatigue or fluid retention due to cardiac dysfunction, either at rest or on exertion, with accompanying neurohormonal activation.”
Features of HF?
HF is common and is more common in the elderly
HF has a high morbidity and mortality
HF places a high healthcare burden on both primary and secondary care
Why is heart failure not a final diagnosis?
heart failure is not a final diagnosis and the term should be qualified by the underlying structural abnormality and cause
- heart failure due to LVSD due to IHD
- heart failure due to severe aortic stenosis
Symptoms of heart failure?
breathlessness
Fatigue
Odema
Reduced exercise capacity
Signs of HF?
Odema
Tachycardia
raised JVP
chest crepitations or effusions
3rd heart sound
Displaced or abnormal apex beat
Investigations for HF?
Echocardiography, Radionuclide ventriculography (RNVG/MUGA), MRI, left ventriculography
Potential screening test for HF?
12 Lead ECG
LVSD very unlikely if ECG normal (90-95% sensitive)
Problems with confidence of interpretation in primary care, must be entirely normal or else loses reliability
BNP (brain (B-type) natriuretic peptide)
Amino acid peptide, can be measured easily in blood
Elevated in heart failure, therefore a low BNP effectively excludes heart failure
Recommended 1st line test in patients with suspected HF
Describe BNP as a screening test for HF?
Highly sensitive test for HF, stable for up to 72hours, ‘bedside’ testing available if desired, relatively inexpensive
Low BNP effectively rules out heart failure or LVSD, elevated BNP indicates need for an echo/cardiac assessment
Many published trials assessing utility of BNP in suspected heart failure, the general population, post MI – vast majority suggest it is a useful and reliable screening test
Which structural abnormalities will cause heart failure?
if severe enough
LV systolic dysfunction – many causes
Valvular heart disease
Pericardial constriction or effusion
LV diastolic dysfunction/heart failure with preserved systolic function/heart failure with normal ejection fraction
Cardiac arrhythmias: tachy or brady
Myocardial ischaemia/infarction (usually via LVSD)
Restrictive cardiomyopathy eg amyloid, HCM
Right ventricular failure: primary or secondary to pul hypertension
Causes of LV systolic dysfunction?
Ischaemic heart disease (usually MI)
Dilated cardiomyopathy(DCM): Means LVSD not due to IHD or secondary to other lesion ie valves/VSD
Severe aortic valve disease or mitral regurgitation
Describe diagnostic evaluation of patients with LVSD?
Take a detailed history: it may provide the answer – ie MI, DM, HBP, post partum, alcohol etc
Hillwalkers…?lyme’s disease, IVDA…?HIV etc
Consider familial DCM: family history
Exclude renal failure, anaemia, TFTs
Possibly do autoantibodies / viral serology, ferritin
Consider need to exclude phaechromocytoma
Consider other causes……sarcoid, muscular dystrophy etc etc
ECG, sometimes CXR, always do an echo
Consider coronary angiography – essential if chest pain, patients <70(?)
CT coronary angiogram instead of cor angio
Consider evaluating for ischaemia/hibernation ie is revascularisation appropriate even if no angina
Cardiac MRI: infarction/inflammation/fibrosis
Most patients should be assessed by a cardiologist
Why is echocardiography an essential investigation?
Identify and quantify
LV systolic dysfunction
Valvular dysfunction
Pericardial effusion / tamponade
Diastolic dysfunction
LVH
Atrial/ventricular shunts / complex congenital heart defects
Pulmonary hypertension / Right heart dysfunction
May not identify constriction / may miss shunts (but you will see atrial dilatation)
Why is LV ejection fraction importnat?
LV ejection fraction is a continuous biological variable
Disease / physiological changes can both decrease and increase the LVEF
The LVEF may be lower than previous but not pathologically low
Analagous to Haemoglobin / anaemia
eg. fall in Hb from 17g/dL to 14.5g/dL
Figures of LV function assessment and LVEF?
normal 55-70%
40-55% mild
30-40%moderate
<30%severe
Describe Biplane modified simpsons rule?
divides LV cavity into multiple slices of known
thickness
diameter
-> volume of each slice
= area x thickness (pr2 x thickness)
thinner slices -> more accurate vol estimate
endocardial border traced accurately
often major technical difficulty with this method
but still one of most accurate method available
relatively easy to perform (but not routinely done)
Describe MUGA scan?
Much easier to obtain an accurate figure for the LVEF
Greater reproducibility
Ionising radiation
No additional structural information
centre specific normal range
Give features of Cardiac MRI?
More accurate than echo
Additional information of tissue characteristics
Expensive, time-consuming
cannot be done at bedside
Requires breathholding
Claustrophobia issues
Describe NYHA classification for heart failure?
I- no exercuse limitation
II- mild limitation
III- moderate limitation
IV- severe limitationn
Grading the severity of HF?
Degree of LV impairment
(or valvular dysfunction etc)
NYHA class ie severity of symptoms
Degree of elevation of BNP
Why does heart failure does not equal reduced cardiac output (at rest): oranges and footballs?
Normal heart (an orange) end diastolic volume 100mls with 60% EF = 60mls blood ejected per beat x 60 bpm = 3.6litres CO per min
Dilated heart (football): with reduced EF: EDV 200mls with 30% EF = 60mls blood ejected per beat x 60bpm = 3.6l CO per min….at100bpm = 6 litres CO per min!
……and yet that person will possibly have severe heart failure….So it is NOT simply about cardiac output
What systems are targetted for systemic HF?
Renin-angiotensin-aldosterone system
salt and water retention
adverse haemodynamics
LV hypertrophy/remodelling and fibrosis
hypokalaemia and hypomagnesaemia
SNS – arrhythmogenic, adverse haemodynamics, increases renin etc
What drugs have given best results for HF?
Pharmacological therapy
Diuretics
ACE inhibitors
Betablockers
Aldosterone receptor blockers
Now ARNI (Angiotensin receptor and Neprolysin Inhibitor)
