Chronic heart failure Flashcards
Define chronic heart failure
Failure of the heart as a pump to meet the circulatory needs which becomes a long term condition
CHF specifically refers to the stage in which fluid builds up around the heart and causes it to pump inefficiently
What are the other names for chronic heart failure?
Congestive heart failure
Congestive cardiac failure (CCF)
What is the major cause of heart failure?
Give secondary causes of CHF
Due to failure of the heart muscle or failure of the heart valves
Maybe chronic/acute (after heart attack)
2ndary causes of CHF:
- IHD (most common)
- Hypertension
- Cardiomyopathies (alcohol, viral)
State what factors may precipitate/worsen heart failure
Pregnancy
Anaemia
Hyper & hypothyroidism
Fluid retaining drugs:
- Glucocorticoids
- NSAIDs
What happens to cardiac output in heart failure?
Include…
- what is cardiac output?
- what is cardiac output a function of?
Cardiac output is the amount of blood your heart is able to pump in 1 minute.
The problem in heart failure is that the heart isn’t pumping out enough blood each time it beats (low stroke volume).
CO is a function of:
- Preload (force that stretches the muscle fibers of the ventricle at the end of diastole)
- Afterload (resistance to ventricular ejection)
- Muscle contractility
Often Ishaemic Heart Disease leads to impaired muscle function
What is a consequence of hypertension?
(For thr increase in afterload) you get hypertrophy
Cardiac enlargement thus increases the work of the heart and lessens the ejection fraction
State the main humoral factors involved in neurohormonal adaptation
The major neurohumoral adaptations that occur in HF, including
- activation of the sympathetic NS
- activation of renin-angiotensin systems
- increased secretion of antidiuretic hormone (ADH)
- increased secretion of atrial natriuretic peptide (ANP)
How does RAAS play a role in heart failure?
State the consequences of neurohormonal adaptation
But this leads to:
- Increased afterload
- Increased circulating volume (increased preload & afterload)
- Increased resistance will lead to impaired renal function, more salt/water retention with further activation of RAAS!
A vicious cycle develops which further impairs the pump activity of the heart
Neurohormonal activation leads to myocyte dysfunction
Distinguish between left and right ventricular failure and biventricular failure
Left-ventricular failure
- caused by hypertension
- impaired LV leads to
- increase in left atrial/pulmonary venous pressure w/ pulmonary oedema (fluid in lungs) - breathlessness
Right-ventricular failure
- Due to lung disease or pulmonary valvular stenosis (narrowing of valves)
- Cause peripheral oedema (ankles)
Biventricular failure
- Both chambers
- Disease (e.g. IHD) has affected both ventricles
- starts with LVF, leads to pulmonary congestion, then RVF starts to fail
What are the signs + symptoms of CHF?
Fatigue, listless (lack of energy)
Poor exercise tolerance (determines grade 1-4 (severe))
Cold peripheries
Low blood pressure
Reduced urine flow
Weight loss
What are the signs + symptoms of left ventricular failure?
Breathlessness (dyspnoea) - drowing sensation (cardiac asthma)
Wet cough
Orthopnoea - breathlessness when lying down (relieved by sitting up/propping up)
Inspiratory crepitations - hearing crackling noise
What are the signs + symptoms of right ventricular failure?
Raised venous pressure
Increased JVP (jugular venous pressure)
Enlarged liver
Oedema (ankles) - if lying down rises to thighs/abdomen
How to diagnose CHF?
Symptoms
Examination
Echocardiogram: Ejection fraction <45%
B-type natriuretic peptide (BNP) levels (blood test)
Chest X-ray
Define atrial fibrillation
LV/valve failure leading to increased pressure in left atria, leading to distension which leads to atrial fibrillation.
Complication = stasis of blood (blood stays still), leading to thrombi which may dislodge and move to cerebral circulation (risk of TIA)
– need for prophylaxis = warfarin (thinning of blood to prevent clot)
