Chronic Heart Failure

Overview

Chronic heart failure is when the heart is unable to pump blood out to the body effectively to meet its demands. It is the result of a structural or functional heart problem leading to impairment of the ventricles to fill or eject blood properly.

People with chronic heart failure are prone to having acute episodes of decompensation (worsening of symptoms). This is discussed in Acute Heart Failure.

It may be helpful to read Heart Failure: An Overview to help with remembering and making sense of this chapter.

Epidemiology

• Prevalence increases with age
• Average age of diagnosis is 77

Classification

By ejection fraction

Overall, heart failure is classified based on the left ventricular ejection fraction (LVEF). This is the amount of blood in the left ventricle that is pumped out with each heartbeat. The LVEF is measured using echocardiography. This is discussed in more detail in Heart Failure: An Overview.

Heart failure is divided into:

• Heart failure with reduced ejection fraction (HFrEF):
  • Ejection fraction <40%
  • Patients usually have systolic dysfunction – impaired ventricular contraction during systole
• Heart failure with preserved ejection fraction (HFpEF):
  • Ejection fraction >40%
  • Patients usually have diastolic dysfunction – impaired ventricular filling during diastole

By severity

The New York Heart Association (NYHA) classification system can classify heart failure based on severity:

• Class I: asymptomatic
  • Ordinary physical activity does not cause breathlessness, fatigue, or palpitations
• Class II: mild symptoms with moderate exertion
  • Comfortable at rest
  • Ordinary physical activity does cause breathlessness, fatigue, or palpitations
• Class III: symptoms with minimal activity
  • Comfortable at rest
  • Less than ordinary physical activity does not cause breathlessness, fatigue, or palpitations
• Class IV: symptoms at rest
  • Unable to carry out any physical activity without symptoms
  • Discomfort worsens with physical activity

Causes

• Coronary heart disease
• Hypertension
• Valvular heart disease
• Cardiomyopathies
• Arrhythmias
• Drugs e.g. beta-blockers, antiarrhythmics, cytotoxic drugs
• Toxins e.g. alcohol, cocaine
• Endocrine: diabetes, hypothyroidism, hyperthyroidism, Cushing’s syndrome, adrenal insufficiency, acromegaly, phaeochromocytoma
• Thiamine deficiency
• Sarcoidosis
• Haemochromatosis
• Connective tissue diseases
• HIV

Risk Factors

• Previous cardiovascular disease
• Previous myocardial infarction
• Hypertension
• Diabetes mellitus
• Increasing age
• Male
• Family history
• Arrhythmia e.g. atrial fibrillation
• Obesity
• Valvular heart disease
• Sleep apnoea
• Hypo- and hyperthyroidism
• Anaemia
• Connective tissue disorders
• Same risk factors for acute heart failure

Presentation

Although heart failure is no longer classified as ‘left-sided’ or ‘right-sided’, this distinction can be used to help with remembering symptoms:

• Left-sided heart failure – results in pulmonary congestion:
  • Cough – may produce pink or frothy sputum
  • Lethargy
  • Dyspnoea
  • Orthopnoea
  • Paroxysmal nocturnal dyspnoea
  • Bibasal fine crackles
  • Wheeze
• Right-sided heart failure – results in systemic congestion:
  • Peripheral oedema, classically ankle or sacral oedema
  • Raised jugular venous pressure
  • Hepatomegaly
  • Weight gain due to fluid retention
  • Anorexia

Differential Diagnoses

Chronic obstructive pulmonary disease

• Dyspnoea is usually episodic and has specific triggers e.g. infection/cold weather
• Usually seen in patients who smoke
• NT-proBNP is not generally elevated unless cor pulmonale develops

Nephrotic syndrome

• The following are seen:
  • Proteinuria (>3.5 g/24hr)
  • Hypoalbuminaemia
  • Oedema
• Other features that may also be seen include:
  • Hyperlipidaemia
  • Hypercoagulability
  • Immunodeficiency

Investigations

Overview

• N-terminal pro-B-type natriuretic peptide (NT-proBNP) – a key initial test:
  • Elevated
  • If >2000ng/L (high) – referral for specialist assessment and echocardiography within 2 weeks
  • If 400-200ng/L (raised) – referral for specialist assessment and echocardiography within 6 weeks
• Full blood count (FBC):
  • May identify anaemia, which can worsen heart failure
• Urea and electrolytes (U&Es):
  • May show hyponatraemia – heart failure can lead to increased water retention and dilution of serum sodium
• ECG – may show:
  • Ventricular hypertrophy
  • Conduction abnormalities
  • Abnormal QRS duration
• Chest x-ray – may show:
  • Pulmonary oedema – Kerley B lines
  • Cardiomegaly
  • Pleural effusions
• Transthoracic echocardiogram:
  • Identifies systolic or diastolic ventricular dysfunction

Management

All patients

• 1^st line: ACE inhibitor (ACEi)/ARB + beta-blocker once ACE inhibitor established
  • Beta-blocker options are: bisoprolol, carvedilol, metoprolol or nebivolol
• 2^nd line: aldosterone antagonist e.g. spironolactone/eplerenone
• Additional treatments:
  • Loop diuretics e.g. furosemide for symptomatic relief
    • These do not improve survival (due to a lack of evidence) but reduce symptoms of fluid overload
  • SGLT-2 inhibitors:
    • Considered as add-on treatments to standard care in HFrEF as evidence shows they reduce hospitalisation due to heart failure
• 3^rd line: initiated by a specialist:
  • If Afro-Caribbean:
    • Hydralazine and isosorbide dinitrate
  • If heart rate >75bpm and ejection fraction <35%:
    • Ivabradine
  • If reduced LVEF, especially for those with atrial fibrillation:
    • Digoxin
  • If LVEF <35% and ACEi/ARB ineffective:
    • Sacubitril-valsartan after ACEi/ARB washout period completed

Other recommendations for all patients

• Annual influenza vaccination
• One-off pneumococcal vaccination

Monitoring

• All patients with heart failure need regular follow-up and monitoring. In general, this is within 2 weeks if their clinical condition or drugs have changed, and at least every 6 months if their condition is stable.
• NICE recommends considering monitoring NT-proBNP in those less than 75 years of age to guide drug treatment.
• Patients should have their U&Es and eGFR monitored every 6 months.

Patient Advice

• Patients should:
  • Regularly monitor their weight – assesses fluid overload
  • Restrict salt and fluid intake
  • Stop smoking
  • Limit alcohol intake
  • Have a balanced and healthy diet
  • Control blood pressure and diabetes
  • Exercise regularly and as much as tolerated

Complications

• Pleural effusion
• Acute heart failure
• Acute kidney injury
  • This could be due to poor perfusion due to heart failure itself or as a side effect of the medications e.g. ACE inhibitors, aldosterone antagonists etc.
• Chronic kidney disease
  • Patients may develop a “cardiorenal syndrome” in which the dysfunction of the heart may lead to dysfunction of the kidneys and vice versa.
  • This is a difficult scenario as medications for heart failure often negatively impact the kidneys
• Anaemia
• Cardiac arrest

Prognosis

• Around 50% of people with heart failure die within 5 years of diagnosis
• Mortality rates appear to be improving
• Factors associated with a worse prognosis are lower ejection fraction, increasing age, smoking, and other comorbidities (e.g. diabetes mellitus, atrial fibrillation, chronic kidney disease, COPD, obesity, or low BMI)