Heart Failure (HF) is a medical condition characterised by the heart’s inability to pump blood efficiently, leading to inadequate circulation and oxygen delivery to meet the body’s needs. Contrary to its name, heart failure does not mean the heart has stopped working; instead, it signifies a weakened or impaired pumping function.
Anatomy and Function of the Heart
The heart, a vital organ in the cardiovascular system, is a muscular pump responsible for circulating blood throughout the body. It is divided into four chambers – the left atrium, left ventricle, right atrium, and right ventricle. The left side of the heart receives oxygenated blood from the lungs and pumps it to the rest of the body, while the right side receives deoxygenated blood from the body and sends it to the lungs for oxygenation.
Explanation of the Pumping Mechanism
The heart’s pumping mechanism involves a coordinated contraction and relaxation of its chambers, facilitated by electrical impulses. The atria contract first, pushing blood into the ventricles. Subsequently, the ventricles contract, sending blood either to the lungs or to the rest of the body, depending on the side of the heart. Valves, such as the mitral and aortic valves on the left side and the tricuspid and pulmonary valves on the right side, ensure unidirectional blood flow and prevent backflow.
What Causes Heart Failure
Heart Failure occurs when the heart’s pumping ability is compromised, leading to inadequate blood circulation. This can result from conditions that weaken the heart muscle or make it work too hard. Common causes include:
Coronary Artery Disease (CAD) – A plaque buildup in the coronary arteries can reduce blood flow to the heart muscle, leading to damage and weakening.
Hypertension (High Blood Pressure) – Persistent high blood pressure forces the heart to pump harder, causing the muscle to thicken and become less efficient over time.
Myocardial Infarction (Heart Attack) – A sudden blockage of blood flow to a part of the heart muscle can lead to permanent damage, impacting the heart’s pumping function.
Cardiomyopathy – Diseases affecting the heart muscle, such as infections or genetic factors, can result in Cardiomyopathy, a condition where the heart muscle weakens.
Heart Valve Disorders – Malfunctioning heart valves, either due to congenital issues or acquired conditions, can disrupt normal blood flow and contribute to Heart Failure.
Chronic Conditions – Diabetes, obesity, and certain lung diseases can strain the heart over time, increasing the risk of Heart Failure.
Types and Stages of Heart Failure
Here are the classifications based on Left or Right Ventricular Involvement:
Left-Sided Heart Failure (LHF)
Systolic LHF – Involves a weakened left ventricle, decreasing the ability to pump blood out to the body.
Diastolic LHF – Involves a stiff left ventricle, impeding proper relaxation and filling during the heart’s resting phase.
Right-Sided Heart Failure (RHF)
Often, it is a consequence of left-sided failure, causing blood to back up into the body, particularly in the veins. Right heart failure may also be secondary to significant lung disease.
Here is the distinction between Systolic and Diastolic Dysfunction:
Systolic Dysfunction
Characterised by a reduced ejection fraction (LVEF ≤ 40%). The heart has difficulty contracting forcefully, leading to decreased pumping efficiency.
Diastolic Dysfunction
Involves the impairment of the heart’s relaxation and filling capacity during the diastolic phase. The ejection fraction may be preserved, but the heart struggles to fill adequately.
Stages of HF - A, B, C, D Classification
The American College of Cardiology (ACC) and American Heart Association (AHA) have established a classification system based on stages of Heart Failure:
Stage A - At Risk
Individuals at risk for developing Heart Failure but without structural heart changes or symptoms. This stage emphasises preventive measures, lifestyle modifications, and addressing risk factors.
Stage B - Structural Heart Disease, No Symptoms
Presence of structural heart changes (such as a reduced ejection fraction) without symptoms. This stage underscores close monitoring and interventions to prevent the progression of Heart Failure.
Stage C - Structural Heart Disease with Symptoms
Structural heart changes are present, and symptoms of Heart Failure, such as fatigue, shortness of breath, and oedema, become evident. Treatment focuses on symptom management, lifestyle changes, and medications to improve heart function.
Stage D - Refractory Heart Failure
Advanced Heart Failure with severe symptoms despite optimal medical therapy. Treatment options may include specialised interventions like heart transplantation or mechanical circulatory support.
Risk Factors for Heart Failure
These risk factors are essential for both prevention and early detection of Heart Failure.
Modifiable Risk Factors
Modifiable risk factors provide opportunities for proactive lifestyle changes, such as adopting a heart-healthy diet, engaging in regular physical activity, managing blood pressure, and quitting smoking.
- Hypertension
- Coronary artery disease
- Diabetes
- Lifestyle factors (diet, physical activity, smoking)
Non-modifiable risk factors highlight the importance of regular health screenings, especially for individuals with a family history of cardiovascular diseases or those belonging to age groups associated with higher risk.
Non-modifiable Risk Factors
- Age
- Family history
- Genetics
Signs and Symptoms of Heart Failure
While some symptoms may manifest acutely, others may develop gradually, emphasising the importance of regular health check-ups, especially for individuals with known risk factors.
Shortness of Breath – Experiencing difficulty breathing, especially during physical activity or while lying down (orthopnoea), can be a prominent symptom of Heart Failure. It occurs due to fluid accumulation in the lungs, limiting their ability to function effectively.
Fatigue and Weakness – Persistent fatigue and weakness are common symptoms of Heart Failure, reflecting the heart’s reduced ability to pump blood efficiently, leading to inadequate oxygen delivery to the body’s tissues.
Swelling (Oedema) in the Legs, Ankles, or Abdomen – Fluid retention, often noticeable as swelling in the lower extremities or abdomen, is a classic sign of Heart Failure. The weakened heart struggles to pump blood effectively, causing fluid to accumulate in surrounding tissues.
Persistent Cough – A chronic cough, often accompanied by white or pink-tinged phlegm, can indicate Heart Failure. Fluid accumulation in the lungs can lead to irritation and coughing.
Understanding Acute and Chronic Symptoms:
Acute Symptoms
Sudden Shortness of Breath – In acute episodes, individuals may experience a sudden onset of severe shortness of breath, even at rest.
Chest Pain – Acute Heart Failure may cause chest pain or discomfort, often resembling heart attack symptoms.
Chronic Symptoms
Gradual Onset of Shortness of Breath – In chronic cases, shortness of breath may develop gradually, worsening over time.
Persistent Fatigue – Chronic fatigue and weakness may persist, impacting daily activities.
Swelling – Oedema in the legs, ankles, or abdomen may become more noticeable over an extended period.
Diagnosis and Evaluation of Heart Failure
These diagnostic tools collectively aid healthcare specialist in confirming a diagnosis of Heart Failure, determining its severity, and guiding treatment decisions. Additional tests, such as cardiac MRI or stress tests, may be recommended in specific cases.
Physical Examination
Healthcare specialists will conduct a thorough physical examination, assessing for signs such as swelling (oedema), elevated jugular venous pressure, and abnormal heart sounds. Lung auscultation helps identify signs of fluid accumulation, such as crackles or wheezing. Peripheral pulses and blood pressure are evaluated to gauge the heart’s efficiency in pumping blood.
Medical History
A detailed medical history helps identify risk factors and potential causes of Heart Failure. Inquiring about symptoms, their duration, and any triggers provides valuable information for diagnosis.
Family history and any pre-existing conditions are crucial components of the medical history.
Echocardiogram
Purpose – An echocardiogram uses ultrasound waves to create detailed images of the heart’s structure and function.
Relevance – It helps assess the heart’s pumping capacity, detect structural abnormalities, and identify any issues with the heart valves.
Blood Tests
Natriuretic Peptides – Elevated brain natriuretic peptide (BNP) or N-terminal pro-B-type natriuretic peptide (NT-proBNP) in the blood can indicate the presence of Heart Failure.
Complete Blood Count (CBC) – To assess for anaemia or infections that may contribute to Heart Failure.
Electrolyte Levels – Imbalances can impact the heart’s rhythm and function.
Electrocardiogram (ECG or EKG)
Purpose – An ECG records the heart’s electrical activity, helping identify irregularities in rhythm and conduction.
Relevance – It can reveal signs of heart damage, such as a previous heart attack, and assess the heart’s electrical stability.
Treatment Approaches
These treatment approaches are often employed in combination, and the choice of intervention depends on the severity of Heart Failure, the underlying cause, and individual patient characteristics. Ongoing monitoring and adjustments to the treatment plan are essential to optimise outcomes and enhance the patient’s quality of life.
Lifestyle Modifications
Heart-Healthy Diet – Emphasize a diet rich in fruits, vegetables, whole grains, and lean proteins. Limit sodium intake to manage fluid retention and blood pressure. Monitor fluid intake to prevent excessive fluid buildup.
Regular Exercise – Engage in regular, moderate-intensity exercise to improve cardiovascular health. A tailored exercise plan can enhance heart function and overall well-being.
Medications
Diuretics
Purpose – Diuretics help eliminate excess fluid from the body, reducing symptoms of fluid retention.
Types – Loop diuretics, thiazide diuretics, and potassium-sparing diuretics are commonly prescribed based on individual needs.
ACE Inhibitors, ARBs, Beta-Blockers
Purpose – These medications improve heart function, manage blood pressure, and reduce the workload on the heart.
ACE Inhibitors (e.g., enalapril) – Dilate blood vessels, improving blood flow.
ARBs (e.g., losartan) – Similar to ACE inhibitors, but with a different mechanism.
Beta-Blockers (e.g., carvedilol) – Reduce the heart’s workload and improve its efficiency.
Sodium-glucose co-transporter inhibitor – Assists in diuresis and improves HF outcomes across the LVEF spectrum
Inotropes and Other Advanced Therapies
Purpose – Inotropes (such as dobutamine) may be used in severe cases to improve heart function temporarily.
Advanced Therapies – Advanced treatments like left ventricular assist devices (LVADs) may be considered for specific cases.
Device Therapy
Implantable cardioverter-defibrillators (ICDs)
Purpose – ICDs monitor heart rhythm and deliver a shock to restore normal rhythm if a life-threatening arrhythmia occurs.
Cardiac resynchronization therapy defibrillator (CRT-D)
Purpose – CRTDs combines an ICD with a special pacemaker that sends electrical impulses to both lower chambers of the heart to help them beat together in a more synchronized pattern. This improves the heart’s ability to pump blood and oxygen to the body and monitors the heart for dangerous arrhythmias, delivering a shock to restore normal rhythm if a life-threatening arrhythmia occurs.
Surgical Interventions
Heart Valve Repair or Replacement
Purpose – Correcting or replacing damaged heart valves improves blood flow and reduces strain on the heart.
Heart Transplant
Purpose – In cases of severe Heart Failure, a heart transplant may be considered when other treatments are no longer effective.
Challenges – Availability of donor organs and compatibility issues limit the feasibility of heart transplants.
