Heart Failure

Definition

Epidemiology

Affects 10% of elderly population

25-50% of patients die within 5 years of diagnosis

Affects 1-3% of the general population

Is a syndrome, rather than a specific diagnosis

Can result from any structural or functional cardiac disorder that impairs the hearts ability to function and meet the demands of the metabolising body

= The inability of the heart to deliver blood and oxygen at a rate that is commensurate with the requirements of the metabolising tissues, despite normal or increased cardiac filling pressures

Treatable not curable

Aetiology

Hypertension

Excess alcohol

Cardiomyopathy - thick, stiff walls

Valve disease

Main cause is IHD

Risk Factors

Men, due to lack of protective effect from oestrogen

Obesity

African descent

Previous MI

65 and older

Pathophysiology

Systems involved in heart failure syndrome

Renin-angiotensin-aldosterone system

Inflammation

Sympathetic system

Ejection Fraction

Reduced ejection fraction = % of blood ejected out of the LV with each beat (about 70%)

In patients with heart failure, the reduced ejection fraction is <50%

The force of contraction is increased, increasing stroke volume and heart rate, thus increasing cardiac ouput

In heart failure, there is chronic sympathetic activation

Baroreceptors stimulate sympathetic activation in response

There are fewer receptors to act on, so sympathetic activation is diminished and cardiac output stops increasing

Baroreceptors in the aorta, carotid and heart walls detect a drop in arterial pressure or an increase in venous pressure

Angiotensin II stimulates the release of aldosterone from the adrenal cortex

Aldosterone increases sodium reabsorption and thus water reabsorption. Also releases ADH to retain water

Angiotensinogen is converted to angiotensin I by renin. Angiotensin I is converted to angiotensin II by ACE

All this results in an increased volume of blood, increasing BP, venous pressure and therefore pre-load and cardiac output

Reduced cardiac output lowers renal perfusion, activating the renin-angiotensin system

The cardiac myocytes need more blood to maintain the increased force of contraction

In heart failure, there is no increased blood flow so the cardiac myocytes die causing a decreased force of contraction and cardiac ouput

Classifications of Heart Failure

Diastolic

Acute

Systolic

Decreased cardiac output

Decreased stroke volume and cardiac output

Pulmonary or peripheral oedema

Ejection fraction <40%

Inability of ventricle to contract normally

Caused by IHD, MI, cardiomyopathy

Ejection fraction >50%

Inability of ventricles to relax and fill fully

Caused by ventricular hypertrophy, pericarditis, tamponade, hypertension

New onset or decompensation of chronic heart failure

Chronic

Develops slowly

Venous congestion is common

Symptoms

Breathlessness

Cold peripheries - not enough energy to metabolise

Ankle swelling

Increased weight due to retaining water and salt

Fatigue

Signs

Murmurs - third heart sound

Displaced apex beat

Tachycardia

Raised JVP

Peripheral and sacral oedema

Hepatomegaly

Ascites

New York Heart Association Classification

Class II: Slight limitation - mild HF

Class III: Marked limitation - moderate HF

Class I: No limitation, asymptomatic

Class IV: Inability to carry out physical activity without discomfort - severe HF

Investigations

Chest X-ray to look for alveolar oedema

ECG

Bloods

Echo - look for regional wall abnormalities and valve disease

U&E

Brain natriuretic peptide (BNP) >100ng/L - secreted by ventricles in response to increased myocardial wall stress. A rise in BNP is higher in left HF than right and with systolic rather than diastolic

FBC

Treatment

Drugs

Complications

DVT

Left bundle branch block

Systemic thromboembolism

Bradycardia

Rhythm disturbance

Hepatic dysfunction

Renal dysfunction

Neurological complications

Surgery

Lifestyle Modification

Stop smoking

Eat less salt

Exercise regularly

Stop drinking alcohol

Lose weight

Beta Blockers

ACE Inhibitors

Diuretics

Nitrates

Decreases pulmonary congestion and oedema

Provide symptomatic relief

Promote sodium and therefore water loss

Thiazide diuretic: bendroflumethiazide

Loop diuretic: furosemide

Aldosterone antagonist (inhibits ADH release): spirolactone

Examples: ramipril

If cough is a problem, give angiotensin receptor blocker

Improves symptoms and prolongs life

Examples: bisoprolol

Do not give to asthmatics!

Start low dose and titrate upwards slowly

The best drug to give to patients with reduced ejection fraction

These are arterial and venous dilators

Mitral valve replacement

LV re-modelling

Aortic valve replacement

Pacemaker to synchronise ventricular beating

Mitral valve repair

Palliative care

Systolic = inability of ventricles to contract, EF<40%. Caused by IHD + cardiomyopathy

Diastolic - inability of ventricles to relax, causes increased filling pressures. EF>50%. Caused by aortic stenosis

Normal EF is 55%-70%

Systolic and diastolic heart failure often co-rexist

When there is left and right sided heart failure, this is called congestive heart failure

Emergency

Low Output HF - not pumping

High Output HF - anaemia, pregnancy, hyperthyroidism. Heart is failing to meet the demands of metabolising tissues