Chronic Heart Failure - 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
Describe the prevalence and incidence of heart failure?
Increases with age - mean age of 74 years
Around 60,000 patients with HF/LVSD in Scotland
Why is there is an increasing risk of CHF?
Treatment of AMI, aging population, increase prevalence and incidence of hypertension, CHD, Obesity, Diabetes and HLP
What can contribute to a decreasing risk of CHF for the population?
Treatment and diagnosis of HLP, Hypertension, CHD, Diabetes and obesity
Describe the prognosis of Heart failure
One-year survival rate for heart failure is worse than for cancer of breast, uterus, prostate and bladder
Also expensive for NHS
Describe hospital re-admissions for people with heart failure
High death rate on initial admission
Re-admissions often happen in first week and are high
Happen usually early
Describe HF in terms of mortality and morbidity
High morbidity and mortality
What are the symptoms of heart failure?
Breathlessness, fatigue, oedema and reduced exercise capacity
What are the clinical signs of heart failure?
Oedema, tachycardia, raised JVP, chest creps or effusions, 3rd heart sound and displaced or abnormal apex beat
What can be seen on an X-ray if patient has HF?
Gross cardiomegaly, pleural effusions and oedema
Can you diagnose HF on clinical grounds alone?
No as difficult cause symptoms and signs are non-specific
Objective evidence for cardiac dysfunction if mandatory
What is needed for diagnosis of Heart failure?
Symptoms or signs of HF (rest or exercise)
Objective evidence of cardiac dysfunction
Response to therapy (diuretics) in doubtful cases
How do you obtain objective evidence of cardiac dysfunction?
Echocardiography, Radionuclide ventriculography (RNVG?MUGA), MRI, left ventriculography
What are potential screening tests for HF?
12 lead ECG - LVSD is unlikely if ECG is normal
BNP (brain natriuretic peptide) - measured easily in blood and is elevated in heart failure
Low BNP can exclude HF
Recommended BNP first line in suspected HF
Describe BNP as a screening test for heart failure
Highly sensitive test for HF and is stable for 72hrs so suitable for community testing
Low BNP rules out HF or LVSD
Elevated BNP indicates need for Echo/ cardiac assessment
Can BNP predict mortality and morbidity?
Yes, Higher BNP then higher risk
What condition if severe enough will cause heart failure?
Any structural cardiac abnormality
Name some structural cardiac abnormalities that could lead to HF if sufficiently severe
LVSD, Valvular heart disease, pericardial constriction or effusion, LV diastolic dysfunction (Heart failure with normal ejection fraction), cardiac arrhythmias, MI, Restrictive cardiomyopathy, and Right ventricular failure
What can causes LV systolic dysfunction?
Ischaemic heart disease
(usually MI)
Dilated cardiomyopathy - LSVD not due to IHD or secondary to other lesion (valves/VSD)
Severe aortic valve disease or mitral regurgitation
What are some causes of dilated cardiomyopathy (DCM)?
Inherited is most common, toxins, viral and other infectives, systemic disease and hypertension…
What can be included in a patients history of LVSD?
MI, DM, HBP, post partum and alcohol.
Lyme disease, IDVA, HIV
Consider familial
Sarcoid, muscular dystrophy
What is good to exclude in a patient when diagnosing LVSD?
Renal failure, anaemia, TFTs (thyroid), pheochromocytoma
What investigations can be used in diagnosis of LVSD?
ECG and sometimes CXR
Always do an Echo
Consider coronary angiography - essential if chest pain and patients over 70
CT coronary angiogram
Cardiac MRI can look for infarction, inflammation and fibrosis
What can an Echo identify and quantify?
LVSD, valvular dysfunction, pericardial effusion/ tamponade, diastolic dysfunction, LVH, Atrial/ ventricular shunts and pulmonary hypertension
What are some benefits and negatives of an echo?
Simple and non-invasive. No ionising radiation
May not identify constriction or may miss shunts but you will see AF or if the heart is under strain
Explain 2D views of an echo?
Parasternal long axis
Parasternal short axis - papillary muscle level
Parasternal short axis - base
What will severe LV systolic dysfunction look like on an echo?
LV more globular shape - dilated
Systolic motion is also impaired
Describe LV ejection fraction
Assesses how impaired LV is
LV ejection fraction is a continuous biological variable
Disease/ physiological changes can both decrease and increase the LVEF
Chemo can lower LVEF
What makes LV ejection fraction difficult to quantify by echo?
Quality of images
Experience of operator
Calculation methods very - M-mode and Simpsons biplane (gold standard)
Use of contrast agents
Time consuming
Describe LV function assessment and LVEF percentage?
Normal - 55-70%
Mild - 40-55%
Moderate - 30-40%
Severe - <30%
Describe Biplane modified Simpsons Rule
Way of calculating the LVEF
Divides LV cavity into multiple slices of known thickness and diameter - is 2D visualising 3D
Volume of each slice - area x thickness - thinner slices are more accurate
Endocardial border traced accurately
Describe an echo constrast
Used to improve endocardial border detection
Lights up the LV cavity and can easily see the border
Describe a MUGA scan
Nucleotide technique - ionising radiation
Greater reproducibility
No additional structural info.
Centre specific normal range
Easier to obtain an accurate figure for the LVEF if heart rhythm is irregular
Describe a cardiac MRI benefits and negatives
More accurate then echo as can get additional info. of tissue characteristics
Is expensive, slow, requires breath-holding and can be claustrophobic
Good for looking at LV hypertrophy
Describe the grading classification of heart failure
NYHA classification
1 - no symptoms
2 - comfortable with rest or mild exercise
3 - comfortable only at rest
4 - any physical activity brings discomfort and symptoms at rest
How do you grade the severity of HF?
Degree of LV impairment (or valvular dysfunction)
NYHA class - severity of symptoms
Degree of elevation of BNP - not used as much
Why does structural abnormalities in the heart cause the syndrome of HF?
HF is not a simple mechanical problem
HF is a systemic disorder - cardiac dysfunction, renal, skeletal, systemic inflammation and neurohormonal activation
How does RAAS contribute to HF?
Salt and water retention
Adverse haemodynamics
LV hypertrophy/ remodelling or fibrosis
Electrolyte disturbances - low K and Magnesium
How does SNS contribute to HF?
Arrhythmogenic
Adverse haemodynamics and increases renin so vicious cycle
Also vasoconstricts
What can left ventricular dysfunction cause?
Arrhythmia, pump failure, neurohormonal activation and HF
