BLOCK 13 WEEK 3 Flashcards
Heart Failure
Heart failure (HF), also known as congestive heart failure (CHF) and congestive cardiac failure (CCF), is defined as the failure of the heart to generate sufficient cardiac output to meet the metabolic demands of the body.
The prognosis for HF varies, but approximately 50% of those diagnosed are alive at 5 years.
Epidemiology of heart failure
HF is common: the prevalence in the UK is estimated at 1-2%.
HF primarily affects the elderly population: the average age of diagnosis is 75 years old. The incidence of HF has been increasing with the ageing population.
HF pathophysiology:
The pathophysiology for HF is diverse and depends on the aetiology of the HF.
How can HF be classified?
HF can be classified in different ways.
It can be classified as being:
- low output vs. high output HF
- predominantly systolic or diastolic dysfunction
- whether the process has been acute or chronic
- or by the severity of symptoms (and consideration for predominantly left or right ventricle features).
low output vs. high output HF
Low-output HF is much more common than high-output HF.
Low-output HF occurs: when cardiac output is reduced due to a primary problem with the heart and the heart is unable to meet the body’s needs.
High-output HF: refers to a heart that has a normal cardiac output, but there is an increase in peripheral metabolic demands that the heart is unable to meet.
Common causes of high output heart failure
The common causes of low-output HF wll be further discussed below. Common causes of high-output HF include:
Anaemia
Arteriovenous malformation
Paget’s disease
Pregnancy
Thyrotoxicosis
Thiamine deficiency (wet Beri-Beri)
Systolic vs Diastolic HF
Systolic dysfunction refers to an impairment of ventricular contraction.
The ventricles are able to fill well, but the heart is unable to pump the blood sufficiently out of the ventricle due to impaired myocardial contraction during systole (reduced ejection fraction).
Common causes include: ischaemic heart disease, dilated cardiomyopathy, myocarditis or infiltration (haemochromatosis or sarcoidosis).
Diastolic dysfunction refers to the inability of the ventricles to relax and fill normally, hence the heart is still able to pump well but pumps out less blood per contraction due to reduced diastolic filling (preserved ejection fraction).
Common causes include: uncontrolled chronic hypertension (significant left ventricular hypertrophy reduces filling of the left ventricle), hypetrophic cardiomyopathy, cardiac tamponade, and constrictive pericarditis.
Acute vs Chronic HF
HF can also be classified according to time of onset. Acute HF occurs with new-onset of HF symptoms (acute mitral regurgitation following an MI) or an acute deterioration in a patient with known, chronic HF.
In comparison, chronic HF progresses more slowly and may take many years to develop.
The clinical features of left heart failure
LHF, or left ventricular failure (LVF), causes pulmonary congestion (pressure builds up on the LHS of the heart and there is backpressure to the lungs) and there is systemic hypoperfusion.
Hypoperfusion: means low blood flow and occurs because of circulatory failure caused by the failing of the heart’s pumping action
Symptoms:
-Shortness of breath on exertion
-Orthopnoea: shortness of breath that occurs while lying flat and is relieved by sitting or standing
-Paroxysmal nocturnal dyspnoea
-Nocturnal cough (± pink frothy sputum)
-Fatigue
Signs:
Tachypnoea
Bibasal fine crackles on auscultation of the lungs
Cyanosis
Prolonged capillary refill time
Hypotension
Less common signs: pulsus alternans (alternating strong and weak pulse), S3 gallop rhythm (produced by large amounts of blood striking compliant left ventricle), features of functional mitral regurgitation.
The clinical features of right heart failure
Right heart failure causes venous congestion (pressure builds up behind the right heart) and pulmonary hypoperfusion (reduced right heart output).
Symptoms:
- Ankle swelling
- Weight gain
- Abdominal swelling and discomfort
- Anorexia and nausea
Signs:
-Raised JVP
-Pitting peripheral oedema (ankle to thighs to sacrum)
-Tender smooth hepatomegaly
-Ascites
-Transudative pleural effusions (typically bilaterally)
Congestive Cardiac Heart Failure
Sometimes left sided heart failure can lead to pulmonary congestion which in turn also pushes the right ventricle into failure. In these cases signs and symptoms of both left and right sided heart failure may be present. This is congestive cardiac failu
Ejection Fraction
Chronic heart failure symptoms
Signs on examination include:
- Tachycardia (raised heart rate)
- Tachypnoea (raised respiratory rate)
- Hypertension
- Murmurs on auscultation indicating valvular heart disease
- 3rd heart sound on auscultation
- Bilateral basal crackles (sounding “wet”) on auscultation of the lungs, indicating pulmonary oedema
- Raised jugular venous pressure (JVP), caused by a backlog on the right side of the heart, leading to an engorged internal jugular vein in the neck
- Peripheral oedema of the ankles, legs and sacrum
Location
Investigating Heart Failure
- Clinical assessment (history and examination)
- N-terminal pro-B-type natriuretic peptide (NT‑proBNP) blood test
- ECG:
ECG may be normal or hint at underlying aetiology (ischaemic changes or arrhythmias). - Echocardiogram
-Transthoracic echocardiogram (TTE)
Echocardiogram will confirm the presence and degree of ventricular dysfunction.
Other investigations include:
-Bloods for anaemia, renal function, thyroid function, liver function, lipids and diabetes
-Chest x-ray and lung function tests to exclude lung pathology
New York Heart Association Classification
The New York Heart Association (NYHA) classification system is used to grade the severity of symptoms related to heart failure. Here is a simplified summary:
Class I: No limitation on activity
Class II: Comfortable at rest but symptomatic with ordinary activities
Class III: Comfortable at rest but symptomatic with any activity
Class IV: Symptomatic at rest
MANAGEMENT OF HEART FAILURE
There are five principles of management. You can remember this with the “RAMPS” mnemonic:
R – Refer to cardiology
A – Advise them about the condition
M – Medical treatment
P – Procedural or surgical interventions
S – Specialist heart failure MDT input, such as the heart failure specialist nurses, for advice and support
The urgency of the referral and specialist assessment depends on the NT-proBNP result. According to the NICE guidelines:
From 400 – 2000 ng/litre should be seen and have an echocardiogram within 6 weeks
Above 2000 ng/litre should be seen and have an echocardiogram within 2 weeks
Medical Treatment of Heart Failure
The first-line medical treatment of chronic heart failure can be remembered with the “ABAL” mnemonic:
A – ACE inhibitor (e.g., ramipril) titrated as high as tolerated
B – Beta blocker (e.g., bisoprolol) titrated as high as tolerated
A – Aldosterone antagonist when symptoms are not controlled with A and B (e.g., spironolactone or eplerenone)
L – Loop diuretics (e.g., furosemide or bumetanide)
An angiotensin receptor blocker (ARB) (e.g., candesartan) can be used instead of an ACE inhibitor if not tolerated. Avoid ACE inhibitors in patients with valvular heart disease until initiated by a specialist.
Aldosterone antagonists are used when there is a reduced ejection fraction and symptoms are not controlled with an ACEi and beta blocker.
Patients should have their U&Es closely monitored whilst taking diuretics, ACE inhibitors and aldosterone antagonists, as all three medications can cause electrolyte disturbances. It is particularly essential to closely monitor the renal function in patients taking ACE inhibitors and aldosterone antagonists. Both can cause hyperkalaemia (raised potassium), which is potentially fatal.
Additional specialist
Loop diuretics
ACE inhibitors and ARBS
DIGOXIN
Side effects of Beta Blockers
SGLT- 2 Inhibitors