Chronic Heart Failure (CHF)

Chronic Heart Failure (CHF) Overview

• CHF is a clinical syndrome characterized by reduced cardiac output due to impaired cardiac contraction.
• Common symptoms include shortness of breath, fatigue, and ankle swelling.
• CHF prevalence is 1-2%, increasing to 10% in individuals over 70 years old.

Aetiology and Pathophysiology

• Stroke volume depends on adequate preload, optimal myocardial contractility (Frank-Starling mechanism), and decreased afterload.
• Reduced cardiac output can be caused by decreased heart rate, decreased preload, decreased contractility, or increased afterload.
• Cardiac Output (CO) = Heart Rate (HR) x Stroke Volume (SV).
• Common causes of heart failure in the UK include coronary heart disease (myocardial infarction), atrial fibrillation, valvular heart disease, and hypertension.
• Other causes include endocrine diseases (hypothyroidism, hyperthyroidism, diabetes), medications (calcium antagonists, anti-arrhythmics, cytotoxic medications, beta-blockers)

HIGH-VIS Acronym for CHF Causes

• Hypertension
• Infection/Immune (viral, bacterial, autoimmune)
• Genetic (hypertrophic obstructive cardiomyopathy (HOCM), dilated cardiomyopathy (DCM))
• Heart Attack (ischemic heart disease)
• Volume Overload (renal failure, nephrotic syndrome, hepatic failure)
• Infiltration (sarcoidosis, amyloidosis, hemochromatosis)
• Structural (valvular heart disease, septal defects)

Clinical Features - History

• Patients often present with gradually worsening symptoms over months to years.
• Typical symptoms include dyspnea on exertion, fatigue limiting exercise tolerance, orthopnea, paroxysmal nocturnal dyspnea (PND), nocturnal cough (possibly with pink frothy sputum), pre-syncope/syncope, and reduced appetite.
• Important aspects of the history include past medical history (hypertension, coronary artery disease, valvular heart disease), medication history (calcium antagonists, antiarrhythmics, cytotoxic medication, beta-blockers), family history (cardiomyopathy, coronary artery disease), and social history (smoking, alcohol, drug use).

Clinical Features - Examination

• Cardiovascular examination findings may include tachycardia, hypotension, narrow pulse pressure, raised jugular venous pressure, displaced apex beat, right ventricular heave, gallop rhythm, murmurs associated with valvular heart disease, and pedal/ankle edema.
• Respiratory examination findings may include tachypnea, bibasal end-inspiratory crackles and wheeze, reduced air entry, and stony dullness on percussion (pleural effusion).
• Abdominal examination findings may include hepatomegaly and ascites.

Investigations - Bedside

• ECG: To check for previous myocardial infarction or arrhythmias. A normal ECG makes heart failure unlikely.
• Urinalysis: To check for glycosuria (diabetes) or proteinuria (renal disease)

Investigations - ECG Findings

• ECG findings associated with heart failure include tachycardia, atrial fibrillation, left-axis deviation, P wave abnormalities (P.mitrale/P.pulmonale), prolonged PR interval, and wide QRS complexes.

Investigations - Laboratory

• FBC: Check for anaemia.
• U&Es: Check for renal failure, electrolyte abnormalities (e.g., hyponatremia).
• LFTs: Check for hepatic congestion.
• Troponin: If considering recent myocardial infarction.
• Lipids/HbA1c: Check for ischaemic risk profile.
• TFTs: Check for hyperthyroidism/hypothyroidism.
• Cardiomyopathy screen
• N-terminal pro-B-type natriuretic peptide (NT-proBNP)

Cardiomyopathy Screen

• Includes serum iron and copper studies, rheumatoid factor, ANCA/ANA, ENA, dsDNA, serum ACE, and serum-free light chains to rule out various conditions.

NT-proBNP

• Levels guide the urgency for echocardiography and specialist assessment:

  • 2000 ng/L: Urgent referral, echocardiography within 2 weeks.

  • 400-2000 ng/L: Routine referral, echocardiography within 6 weeks.
  • <400 ng/L: Heart failure is unlikely.

Imaging - Chest X-Ray

• Typical signs include cardiomegaly, increased vascular markings in the upper lobes, Kerley B lines, perivascular cuffing, and pleural effusions.

Imaging - Cardiac MRI

• Cardiac MRI is the gold standard investigation for assessing ventricular mass, volume and wall motion.
• Can be used with contrast to identify infiltration, inflammation or scarring.
• Typically used when echocardiography has provided inadequate views.

Classification - Structural

• CHF is classified based on left ventricular ejection fraction (LVEF).
• LVEF is the percentage of blood that enters the left ventricle in diastole that is subsequently pumped out in systole.
• LVEF is usually measured using transthoracic echocardiography, however, MRI, nuclear medicine scans and transoesophageal echocardiography can also be used.

Classification - Symptomatic/Functional (NYHA)

• Class I: No symptoms during ordinary physical activity.
• Class II: Slight limitation of physical activity by symptoms.
• Class III: Less than ordinary activity leads to symptoms.
• Class IV: Inability to carry out any activity without symptoms.

Management - General

• The focus is to improve cardiac function and quality of life, prevent hospitalisation, and reduce mortality.
• Lifestyle adjustments include fluid and salt restriction, regular exercise, smoking cessation, and reduced alcohol intake.
• All patients should be vaccinated against influenza and pneumococcal disease.
• Perform medication review - Identify medications which may be harmful in the context of heart failure such as Calcium channel blockers, Tricyclic antidepressants, Lithium, NSAIDs & COX-2 inhibitors, Corticosteroids and QT-prolonging medications
• Regular monitoring of functional capacity, fluid status, cardiac rhythm, cognitive status, nutritional status, and renal function is essential.
• Coronary artery disease - Statins and aspirin can be prescribed as secondary prevention.
• Atrial fibrillation - Oral anticoagulation is recommended.

Management - Pharmacological

• Aims to optimize preload and contractility while reducing afterload.
• Medications target the sympathetic response and renin-angiotensin-aldosterone system (RAAS).

Medications - Diuretics

• Prescribed to relieve fluid overload symptoms.
• Work by increasing sodium excretion via diuresis, reducing cardiac afterload.
• Monitor renal function and titrate doses based on clinical response.

Medications - ACE Inhibitors

• Prescribed for patients with reduced ejection fraction (≤40%).
• Improve ventricular function and reduce mortality.
• Check U&Es before starting and after 1-2 weeks of treatment.
• Contraindications include history of angioedema, bilateral renal artery stenosis, hyperkalemia (>5 mmol/L), severe renal impairment, and severe aortic stenosis.

Medications - Beta-Blockers

• Prescribed for symptomatic heart failure with reduced LVEF (≤40%).
• Decrease heart rate, myocardial oxygen demand, and RAAS activation.
• Monitor blood pressure and heart rate when adjusting doses.
• Contraindications include asthma, 2nd or 3rd-degree AV block, sick sinus syndrome, and sinus bradycardia.

Medications - Angiotensin-II Receptor Antagonists (ARBs)

• Prescribed as an alternative if a patient cannot tolerate an ACE inhibitor.
• Patients must have normal serum potassium and adequate renal function.

Medications - Mineralocorticoid/Aldosterone Receptor Antagonists (MRAs)

• Prescribed if symptoms persist despite diuretics, ACE inhibitors, and beta-blockers.
• Increase sodium excretion via diuresis, decreasing cardiac afterload.

Medications - SGLT2 inhibitors

• Can be used as add-on therapy in patients with a reduced LVEF