What are the main types of heart failure? 

Heart failure is not a single condition but a collection of issues that affect how well the heart pumps blood.  Doctors classify heart failure into different types based on which side of the heart is affected and whether the heart muscle is too weak or too stiff.  Understanding which type you have is essential because it influences the specific treatments and medications your medical team will prescribe. 

What We’ll Discuss in This Article 

• The difference between left-sided and right-sided heart failure 

• Understanding heart failure with reduced vs preserved ejection fraction 

• The distinction between acute and chronic heart failure 

• Common causes for each type 

• How symptoms differ depending on the affected side 

• Triggers that can worsen the condition 

• When to seek emergency medical help 

Left-sided heart failure 

Left-sided heart failure is the most common type.  It occurs when the left ventricle, the heart’s main pumping chamber, cannot pump blood effectively to the rest of the body.  Because the left side cannot clear the blood coming from the lungs, fluid backs up into the lung tissue, causing breathlessness. 

Two Main Subtypes 

Medical professionals, including those at the British Heart Foundation, further divide left-sided heart failure into two categories based on ‘ejection fraction’ (a measurement of how much blood is squeezed out with each beat): 

• Heart failure with reduced ejection fraction (HFrEF): Also known as systolic failure. The left ventricle becomes enlarged and weak, meaning it cannot squeeze hard enough to pump the required amount of blood.  

• Heart failure with preserved ejection fraction (HFpEF): Also known as diastolic failure.  The left ventricle muscle becomes stiff and thick. It can still pump, but it cannot relax enough to fill with blood properly. 

Clinical Context 

This type is frequently caused by coronary heart disease or long-term high blood pressure, which puts extra strain on the left ventricle. 

Right-sided heart failure 

Right-sided heart failure typically happens as a result of left-sided heart failure.  When the left side fails, fluid pressure builds up in the lungs, which eventually damages the right side of the heart.  The right ventricle then loses its pumping power, causing blood to back up in the body’s veins.  

Key Mechanism 

The right side of the heart is responsible for pumping blood to the lungs to pick up oxygen.  When it fails, fluid is forced out of the veins and into the surrounding tissues.  

Visible Symptoms 

This leads to swelling (oedema) primarily in the: 

• Feet and ankles 

• Legs 

• Abdomen (causing bloating)  

• Lower back (if bedbound) 

Acute vs Chronic Heart Failure 

Heart failure is also classified by how quickly it develops and how long it lasts. Most people have chronic heart failure, but acute episodes can be life-threatening. 

Chronic Heart Failure 

This is a long-term condition where symptoms develop slowly over time.  The heart gradually becomes weaker or stiffer.  According to the NHS, many patients live with this stable condition for years, managing it through medication and lifestyle adjustments. 

Acute Heart Failure 

This describes the sudden onset of severe symptoms or a rapid worsening of existing chronic heart failure.  It is a medical emergency requiring immediate hospital admission.  Common causes include a sudden heart attack, a severe infection, or a sudden uncontrolled irregular heart rhythm.  

What causes the different types? 

Different underlying health issues tend to trigger specific types of heart failure. Identifying the root cause is the first step in the NICE guidelines for management. 

Causes of Left-Sided Failure 

• Coronary artery disease: Blocked arteries reduce blood flow to the heart muscle.  

• Heart attack: Scar tissue from a previous attack interferes with pumping.  

• High blood pressure: Forces the heart to work harder to pump blood into the body.  

• Valve disease: E.g., aortic stenosis.  

Causes of Right-Sided Failure 

• Left-sided heart failure: The most common cause. 

• Lung diseases: Conditions like COPD or pulmonary hypertension increase pressure in the lungs, straining the right ventricle.  

• Congenital heart defects: Structural problems present at birth.  

Triggers 

For patients with diagnosed heart failure, certain factors can trigger an acute episode or worsening of the condition.  

• Dietary Salt: Excess salt causes fluid retention.  

• Medication Non-adherence: Stopping diuretics or blood pressure medication. 

• Alcohol: Heavy drinking weakens the heart muscle (alcoholic cardiomyopathy).  

• Infection: Flu or pneumonia adds stress to the cardiovascular system.  

Differentiation: Left vs Right Symptoms 

While many patients eventually develop ‘biventricular failure’ (affecting both sides), the symptoms often point to one side initially. 

Left-Sided Symptoms (Lung Focus) 

• Severe breathlessness, especially during activity.  

• Orthopnoea: Need to sleep propped up on pillows to breathe. 

• Paroxysmal Nocturnal Dyspnoea: Waking up suddenly gasping for air.  

• Persistent dry or wheezy cough. 

Right-Sided Symptoms (Body Focus) 

• Swelling in legs, ankles, and feet.  

• Swollen abdomen (ascites). 

• Loss of appetite or nausea (due to fluid in the digestive system).  

• Sudden weight gain due to fluid retention.  

Conclusion 

Heart failure is categorised into left-sided, right-sided, acute, and chronic types, each with specific mechanisms and symptoms. Left-sided failure primarily causes breathing issues due to fluid in the lungs, while right-sided failure leads to swelling in the body. Regardless of the type, the condition requires careful medical management to stabilise the heart and improve quality of life. 

Emergency Guidance 

If you experience severe difficulty breathing, chest pain that spreads to your arms or jaw, or sudden rapid swelling, call 999 immediately. These signs indicate acute heart failure or a heart attack requiring urgent care. 

FAQ Section 

Authority Snapshot 

This article was written by Dr. Rebecca Fernandez, a UK-trained physician with extensive experience in cardiology, internal medicine, and emergency care. Dr. Fernandez has managed critically ill patients and provided comprehensive care for acute and chronic conditions within the NHS framework. This guide draws upon established NHS and NICE guidelines to explain the different classifications of heart failure, ensuring accurate and medically safe information.