Heart Failure Flashcards
Define heart failure.
Severe failure of the heart to function properly, so the heart is unable to pump enough blood to meet the body’s demmands.
How is heart failure defined based on LVEF?
Heart failure with reduced ejection fraction (HFrEF)
Heart failure with mid-range ejection fraction
(HFmrEF) Heart failure with preserved ejection fraction (HFpEF)
Heart failure with reduced ejection fraction (HFrEF)
LVEF <40%
Heart failure with mid-range ejection fraction (HFmrEF)
LVEF 40-49%
Heart failure with preserved ejection fraction (HFpEF)
LVEF >50%
What is the most common form of heart failure?
HFrEF due to impaired contraction of the left ventricle.
What is heart failure caused by?
Heart failure is caused by a structural and or functional cardiac abnormality that results in reduced cardiac output or elevated intracardiac pressures at rest or during stress.
In patients with HFrEF what does myocardial injury result in?
Myocardial injury results in maladaptive changes in myocytes and extracellular matrix which leads to pathological ventricle remodelling with ventricular dilation, and impaired ventricular contraction.
Cycle of HF with reduced ejection fraction:
Right heart failure progression
What does sustained RAAS system activation in heart failure lead to?
What does sustained activation of the SNS in HF lead to?
Explain the role of natriuretic peptides in cardioprotection.
What are natriuretic peptides released in response to?
The stretching of heart muscles.
How do natriuretic peptides function as important biomarkers in heart failure?
As heart failure progresses, activation of the SNS and RAAS system leads to increased blood volume and sustained myocardial stretch, resulting in elevated levels of circulating BNP.
Natriuretic peptides oppose the actions of RAAS, how is this affected in heart failure?
In heart failure, peripheral resistance to NP’s occurs, which results in RAAS signalling being unopposed.
- Reduced NP action in heart failure contributes to the volume overload and vasoconstriction.
Progression of HFrEF can be attributed to two main mechanisms:
- Additional myocyte death due to occurence of events such as recurrent myocardial infarction.
- Decline in systolic functioning triggers a response in neurohormonal signalling pathways, which initiates systemic responses that cause additional strain on the heart.
Neurohormonal signalling pathways activated in HFrEF:
New York Heart Association Classification of Heart Failure:
Diabetes and hypertension are two conditions that increase the risk of developing and worsen the prognosis of heart failure.
- renal dysfunction is also closely linked.
Diabetes and hypertension are two conditions that increase the risk of developing and worsen the prognosis of heart failure.
- renal dysfunction is also closely linked.
What are the clinical presentations of heart failure?
- Assessment of baseline NYHA
- BP/Sats/HR
- Orthopnoea/pillows/sleeping/appetite
- Chest examination/JVP
- Heart sounds/added sounds/murmurs
- Abdo/ascites/hepatic distension
- Peripheral/odema/rash/muscle bulk-cardiac cachexia
What is meant by cardiorenal syndrome?
Cardiorenal syndrome (CRS) is an umbrella term used in the medical field that defines disorders of the heart and kidneys whereby “acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other”.
What routine lab tests are done to investigate
FBC +/- iron studies - ensure patient is not anaemic.
U+E+creatinine or GFR to test kidney function.
HBA1c - blood sugar.
Albumin and clotting - to chest liver function.
BNP - biomarkers.
Cholesterol and lipids.
Functions of BNP
Vasodilation, natriuresis, diuresis.
What is the normal LVEF?
A normal left ventricular ejection fraction (LVEF) ranges from 55% to 70%.
What investigations are done in suspected heart failure?
Transthoracic Echocardiography
ECG
Radionuclide angiography - for LVEF
CMR