Heart Failure Flashcards
What is the pathophysiological definition of chronic heart failure?
- syndrome in which despite normal or raised filling pressures, the heart is unable to maintain an adequate circulation to meet the requirements of normal metabolism
- excludes causes such as haemarrohage and dehydration - result in decreased CO but not caused by abnormality of cardiac function
What is the clinical definition of heart failure?
A clinical syndrome which is caused by an abnormality of hte heart, and characterised by a recognisable pattern of haemodynamic, renal, neural and hormonal responses
What are the 2 CARDINAL SYMPTOMS of heart failure?
Breathlessness and fatigue
What are 4 symptoms of LEFT heart failure?
- Dyspnoea
- Cough - may be worse at night, pink/frothy sputum
- Orthopnoea
- PND: paroxysmal nocturnal dyspnoea
- Fatigue
What are 5 SIGNS of left heart failure?
- Tachycardia
- Crepitations in lung bases - bibasal crackles
- Cardiac wheeze
- Weight loss: cardiac cachexia
- Gallop rhythm
What are 4 symptoms of RIGHT heart failure?
- Ankle swelling
- Fatigue
- Dyspnoea
- Right upper quadrant discomfort
What are 3 signs of right heart failure?
- Elevated JVP
- Oedema/ascites
- Hepatomegaly - sometimes
What are 4 key investigations for chronic heart failure?
- ECG
- CXR
- Echocardiagram - to define nature of cardiac abnormality
- Plasma BNP (B-type natriuretic peptide) - if normal can EXCLUDE diagnosis of heart failure
What causes the increase in B-type natriuretic peptide (BNP) in chronic heart failure?
Peptide released from venricle in response to ventricular stretch
Why is chronic heart failure becoming more common?
More patients now surviving MI: causes left ventricular damage, results in clinical syndrome of heart failure
What are 2 methods to classify causes of heart failure?
-
Physiological classification
- diastolic (impaired cardiac filling) vs systolic
- preload vs afterload
-
Anatomical classification
- Pericardial
- myocaridal
- endocardial
What is are 2 causes of the pericardial form of heart failure?
- Caused by pericardial effusion and tamponade; the high pressure prevents right ventricular filling, resulting in low cardiac output
- Pericardial constriction: syndrome in which a previously inflamed pericardium contracts and fibroses around the heart, preventing cardiac filling
What is the most common anatomical type of chronic heart failure?
Myocardial
What are 6 cases of myocardial heart failure?
- Coronary artery disease - 80% of all
- Hypertension
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Myocarditis
- ‘Heart muscle diseases’ - infiltrative, endocrine, metabolic, neuromuscular, drugs and toxins
What are 5 types of ‘heart muscle diseases’ which can cause myocardial heart failure?
- Infiltrative: sarcoid, myeloid
- Endocrine: diabetes, hyperthryoidism, acromegaly
- Metabolic: haemochromatosis, due to iron overload
- Neuromuscular: drugs and toxins - alcohol, cytotoxics
- Drugs and toxins: alcohol, cytotoxics
What is the commonest cause of myocardial heart failure
Coronary artery disease - 80% of all
How does coronary artery disease lead to heart failure?
In most cases there is a history of myocardial infarction or angina
In some, disease can be silent and can only be diagnosed with appropriate investigation
What are 3 investigations required in suspected heart failure caused by coronary artery disease? What do they show?
- Echocardiography: regional wall-motion abnormalities of left ventricular function
- Cardiac MR scanning: can show areas of infarction
- Cardiac angriography - often required
What is the second most common cause of myocardiac heart failure, after coronary artery disease?
Hypertension
What are 3 causes of endocardial heart failure?
- valvular disease: aortic stenosis most common form in UK due to ageing population
- endocardial fibrosis (eosinophilic)
- Congenital lesions: ASD, VSD
Which of the two cardiac MRIs shows a normal heart and what is the difference?
Left is normal; right shows patient with left ventricular damage due to previous MI: left ventricle dilated, assuming spherical (abnormal) shape
How does diastolic dysfunction (40% of cases) cause heart failure?
Stiff ventricles results in inadequate filling. May be due to age, and cardiac response to increasing arterial stiffness with increasing age
What is the prognosis of heart failure?
Very poor - 5-10% annual mortality, likely to result in death of patient within a few years
Why is prognosis likely to be so poor in heart failure?
- Compensatory neural and hormonal responses in are deleterious in the long term. Leads to positive feedback and a vicious circle
Explain why compensatory mechanisms in heart failure lead to a vicious cycle, responsible for its poor prognosis.
- cardiac lesion leads to decreased cardiac output →
- leads to compensatory mechanisms in the sympathetic nervous system (autonomic) and RAAS
- these can cause further myocardial damage and ventricular dilatation (Laplace’s law), i.e. adverse loading
- damage to ventricle results in left ventricular remodelling
- kidney - abnormalities occur in response
- peripheral vessels - abnormalities occur in response
What is meant by adverse ventricular remodelling in heart failure?
- Even a small heart attack resulting in an area of infarction around the apex tends to result in progressive left ventricular dilatation and thinning
- shape changes from ellipse to sphere
- dilatation results in mechanically inefficient structure
What is the aim of treatment of heart failure?
Palliative: aim to improve symptoms and life expectancy, but don’t restore pumping capacity of heart
Options are aimed at treating the kidney and peripheral vasculature
What are 9 aspects of treatment of heart failure?
- Lifestyle measures
- Treat correctible causes
- ACE inhibitors
- beta blockers
- Diuretics
- Inotropes
- Spironolactone
- Implanted cardioversion defibrillators (ICD)
- Biventricular pacing
What are 5 lifestyle/simple measures to tackle heart failure?
- Fluid restriction: 1.5L per day
- No added salt to avoid fluid retention due to sodium retention
- Exercise
- Compliance with medication
- Stop ‘bad drugs’ e.g. NSAIDs which act on renal prostaglandin metabolism - need to preserve renal function
What can the use of NSAIDs in heart failure result in?
- Act on renal prostaglandin metabolism
- Can result in renal failure and fluid retention - big problems in heart failure
What are 5 correctible causes of heart failure that can be treated?
- Hypertension - give anti-hypertensives
- Drain pericardial fluid - for pericardial effusion/tamponase
- Remove pericardium - see above
- Valve replacement - for valvular endocardium cause
- CABG - coronary artery bypass graft - for myocardial disease due to coronary artery disease
What is the first line treatment for all patients with heart failure?
BOTH an ACE-inhibitor and a beta-blocker
How should an ACE-inhibitor and beta blocker be started to treat chronic heart failure?
Generally, one drug should be started at a time; NICE advice that clinical judgement should be used when determining which to start first
What are 3 beta blockers licensed to treat heart failure in the UK?
Bisoprolol, carvedilol, nebivolol
When do ACE-inhibitors and beta-blockers have no effect on mortality in heart failure?
In heart failure with preserved ejection fraction