Chronic Heart Failure:epidemiology, investigation and diagnosis Flashcards
What is the definition of 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
What is the prevalence of heart failure and of asymptomatic LVSD?
Heart failure: 0.4 - 2%
Asymptomatic LVSD: 0.4 - 2%
Prevalence and incidence increase with age (mean age 74years)
Estimated 40-60 000 patients with HF/LVSD(left ventricular systolic dysfunction) in Scotland
What is the largest cost attached to heart failure
Hospital inpatient care
What can be said about re-admission rates for HF?
High! and readmission is most likely to happen early.
Length of hospital admission is longer than any other condition.
What are the signs of heart failure?
Breathlessness
Fatigue
Oedema
Reduced exercise capacity
What are the signs of heart failure?
Oedema
Tachycardia
Raised JVP
Chest crepitations or effusions
3rd Heart sound
Displaced or abnormal apex beat
Is heart failure easy to diagnose based on clinical signs alone?
Yes very difficult - diagnosis incorrect in approximately 40-50% of cases
What are the 3 key features that indicate heart failure?
Symptoms and signs of HF (rest or at exercise)
Objective evidence of cardiac dysfunction and in (doubtful cases)
Resonse to therapy
(They look like they have it, tests think they have it, and they respond to treatment)
What is objective evidence of cardiac dysfunction?
•Echocardiography, Radionuclide ventriculography (RNVG/MUGA), MRI, left ventriculography
What are the screening tests available?
12 lead ECG - left ventricular systolic dysfunction is very unlikely if there is a normal ECG but it is still possible (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 bood
–Elevated in heart failure, therefore low BNP effectively excludes heart failure
Potential as diagnostic/ screening test for long time
What does a high / low BNP indicate?
•Low BNP effectively rules out heart failure or LVSD, elevated BNP indicates need for an echo/cardiac assessment
What is the common rule as to what will cause heart failure?
If sufficiently severe almost any structural cardiac abnormality will cause heart failure
e.g
- 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
What are common 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
e.g
–Inherited
–Toxins: eg alcohol, catecholamines (phaeochromocytoma or stress cardiomyopathy (takosubo’s cardiomyopathy)
–Viral: acute myocarditis or chronic DCM
–Other infective: HIV, chaga’s disease, Lyme’s disease…….
–Systemic disease: sarcoidosis, haemachromatosis, SLE, mitochondrial dis.
–Muscular dystrophies
–Peri-partum cardiomyopathy (post pregnancy)
–Hypertension
–Isolated non compaction
–Tachycardia related cardiomyopathy
–RV pacing induced cardiomyopathy
–End stage hypertrophic cardiomyopathy
–End stage arrhythmogenic RV cardiomyopathy
Severe aortic valve disease or mitral regurgitation
How do you figure out which type of heart failure is present? IHD, valvular disease or dilated cardiomyopathy
Take a detailed history - may provide answer
Esculde renal failure, anaemia, thyroid function tests
Serology to check for viruses and autoantibodies
Consider to exclude phaechromocytoma (cancer in the adrenal gland)
Consider other causes such as thyroid, muscular dystrophy
ECG, ECHO and sometimes a CXR
Consider coronary angiography in patients with chest pain who are over 70.
Cardiac MRI looking for infarction, inflammation and fibrosis
Why is echocardiography always an essential investigation?
Assesses:
–LV systolic dysfunction
–Valvular dysfunction
–Pericardial effusion / tamponade
–Diastolic dysfunction
–LVH
–Atrial/ventricular shunts / complex congenital heart defects (ventral septal defects)
–Pulmonary hypertension / Right heart dysfunction
•May not identify constriction / may miss shunts (but you will see atrial dilatation)
What changes LVEF?
•Disease / physiological changes can both decrease and increase the LVEF - it is however a continuous biological variable like haemoglobin / anaemia
Can LV ejection fraction be calculated by echo?
Yes but it is difficult to quantify accurately and reproducably
Depends on:
–Quality of images
–Experience of operator
–Calculation method –
- M-mode
- Simpson’s biplane
–Use of contrast agents
–Time-consuming to perform accurately
–Normal range is centre specific, but LVEF not routinely measured and NR not routinely established
What are the normal, mild, moderate and severe LVEF?
- normal (50-80%)
- mild (40-50%)
- moderate (30-40%)
- severe (<30%)
What is LVEF MUGA?
- Much easier to obtain an accurate figure for the LVEF
- Greater reproducibility
- Ionising radiation
- No additional structural information
- centre specific normal range
What is a potent predictor of death in hospitalized heart failure patients?
Left ventricular systolic function
Not really in learning outcomes
Does heart failure always reduce cardiac output?
NO - very complex problem
Why is HF considered a systemic disorder?
Because it involves cardiac dysfunction, renal dysfunction, skeletal muscle dysfunction, systemic inflammation and neurohormonal activation
How is the renin - angiotensin - aldosterone system affected by systemic HF?
Causes salt and water retention (by reduced blood flow to the kidneys)
Adverse haemodynamics
Causes an increase in blood volume - causes LY hypertrophy / remodelling and fibrosis (of LV)
Hypokalaemia and hypomagnesaemia
How does neurohormonal activation affect the sympathetic nervous system?
It is arrythmogenic, adverse haemodynamics, increase in renin etc
What is Left ventricular injury a result of?
Coronary artery disease
Hypertension
Cardiomyopathy
Valvular heart disease
Neurohormonal activation - for example renin-angiotensin-aldosterone system)
What is the result of left ventricular injury?
Left ventricular dysfunction - leading to pump failure, arrythmia, heart failure and even death
What are the outcomes of neurohormonal activation?
Vasoconstriction
Endothelial dysfunction
Renal sodium retention
What are the resultant symptoms of neurohormonal ativation?
Dyspnoea
Fatigue
Oedema
HEART FAILURE
What is modern pharmacological treatment of heart failure?
–Diuretics
–ACE inhibitors
–Betablockers
–Aldosterone receptor blockers
–ARBs
In some patients, ACEI or ARB are now replaced by
ARNI’s: angiotensin receptor neprilysin inhibitor – makes use of beneficial neurohormonal systems (BNP?)
