Diastolic (i.e. Filling) Function: An Overview

Diastolic function is a crucial aspect of heart health, as it refers to the ability of the heart’s ventricles to relax and fill with blood between contractions. Proper diastolic function is essential for maintaining adequate blood flow throughout the body.

This page explores the concept of diastolic function in detail, including its definition, the seriousness of impaired diastolic function, its types, symptoms, causes, and treatment options. Additionally, we discuss the vital role of heart scans in diagnosing diastolic dysfunction and emphasise the importance of seeking care from a professional cardiac clinic.

What is Diastolic Function?

Diastolic function refers to the phase of the cardiac cycle during which the heart’s ventricles relax and fill with blood following a contraction (systole). This phase is essential for ensuring that the heart has an adequate volume of blood to pump out to the body during the next contraction.

Diastolic function involves two main processes:

1. Ventricular Relaxation: The ability of the ventricles to relax quickly and efficiently after contracting, allowing them to fill with blood.
2. Ventricular Filling: The process by which blood flows from the atria into the ventricles during diastole. This filling is influenced by the pressure in the atria and the compliance (flexibility) of the ventricular walls.

Healthy diastolic function is vital for maintaining proper cardiac output and ensuring the body’s tissues receive the oxygen-rich blood they need. When diastolic function is impaired, the heart may struggle to fill adequately, leading to multiple health issues.

How Serious Is It? & Are There Different Types?

Impaired diastolic function, also known as diastolic dysfunction, is a serious condition that can lead to heart failure if left untreated. Diastolic dysfunction is typically classified into different grades based on its severity:

1. Grade 1 (Mild Diastolic Dysfunction): This is often referred to as “impaired relaxation” and is the earliest stage of diastolic dysfunction. In this stage, the ventricles are slower to relax, but the overall filling is still adequate due to compensatory mechanisms. Many individuals with grade 1 diastolic dysfunction may not experience noticeable symptoms.
2. Grade 2 (Moderate Diastolic Dysfunction): Also known as “pseudonormal filling,” this stage represents a more advanced level of dysfunction. The ventricles struggle more significantly to relax, and the heart begins to compensate by increasing filling pressures. Symptoms such as shortness of breath and fatigue may start to appear.
3. Grade 3 (Severe Diastolic Dysfunction): In this stage, also known as “restrictive filling,” the ventricles are stiff and unable to relax properly, leading to significantly impaired filling. This stage is associated with elevated filling pressures and symptoms of heart failure, such as severe shortness of breath, swelling, and exercise intolerance.

Diastolic dysfunction can lead to heart failure with preserved ejection fraction (HFpEF), a condition where the heart’s ability to pump blood is normal, but its ability to fill is compromised, leading to insufficient cardiac output.

Symptoms

The symptoms of diastolic dysfunction may vary depending on the severity of the condition and may include:

• Shortness of breath: Especially during physical activity or when lying down.
• Fatigue: A persistent feeling of tiredness, even with minimal exertion.
• Swelling: Particularly in the legs, ankles, and feet, due to fluid buildup.
• Chest discomfort: Although less common, some individuals may experience chest pain or discomfort.
• Palpitations: A sensation of irregular or rapid heartbeats.
• Exercise intolerance: Difficulty performing physical activities that were previously manageable.

Causes

Diastolic dysfunction can result from various factors and underlying conditions:

• Hypertension: Chronic high blood pressure is a leading cause of diastolic dysfunction. Over time, hypertension can cause the ventricular walls to thicken (left ventricular hypertrophy), reducing their ability to relax and fill properly.
• Ageing: As people age, the heart’s tissues become stiffer, which can impair diastolic function.
• Coronary artery disease (CAD): Blockages in the coronary arteries can lead to ischemia (reduced blood flow) and damage to the heart muscle, affecting its ability to relax.
• Diabetes: High blood sugar levels can damage the heart’s blood vessels and contribute to stiffening of the ventricular walls.
• Obesity: Excess body weight can strain the heart and contribute to the development of diastolic dysfunction.
• Valvular heart disease: Conditions such as aortic stenosis or mitral regurgitation can increase the workload on the heart, leading to diastolic dysfunction.
• Cardiomyopathy: Diseases that affect the heart muscle, such as hypertrophic cardiomyopathy or restrictive cardiomyopathy, can impair diastolic function.

Available Treatments

Treatment for diastolic dysfunction focuses on managing the underlying causes, alleviating symptoms, and preventing the progression to heart failure. Treatment options include:

• Lifestyle changes: Adopting a heart-healthy lifestyle is crucial for managing diastolic dysfunction. This includes regular exercise, a low-sodium diet, weight management, and quitting smoking.
• Medications: Various medications may be prescribed to manage blood pressure, reduce fluid buildup, and improve heart function. These may include diuretics, beta-blockers, calcium channel blockers, and ACE inhibitors.
• Blood pressure control: Maintaining optimal blood pressure is essential for preventing further damage to the heart and improving diastolic function.
• Treating underlying conditions: Managing conditions like diabetes, coronary artery disease, and obesity can help improve diastolic function and reduce symptoms.
• Surgical intervention: In cases where diastolic dysfunction is caused by valvular heart disease, surgery may be necessary to repair or replace the affected valve.

The Role of Heat Scans in Identifying The Issue

Heart scans are critical for diagnosing diastolic dysfunction and assessing its severity. These imaging tests allow cardiologists to evaluate the heart’s structure, measure diastolic function, and identify any underlying conditions contributing to the dysfunction. Common heart scans used in diagnosing diastolic dysfunction include:

• Echocardiogram: An ultrasound of the heart that provides detailed images of the heart’s chambers and valves. It can measure the rate of ventricular relaxation, assess the size and thickness of the heart chambers, and estimate filling pressures.
• Doppler Echocardiography: A specialised type of echocardiogram that measures blood flow through the heart’s chambers, helping to identify abnormalities in diastolic filling.
• Cardiac MRI: Offers a comprehensive view of the heart’s structure and function, including detailed measurements of ventricular relaxation and filling.
• Cardiac CT Scan: Provides high-resolution images of the heart’s anatomy, helping to identify structural abnormalities that may contribute to diastolic dysfunction.

The Importance of Trusting a Professional Cardiac Clinic

Given the complexity and potential seriousness of diastolic dysfunction, it is essential to seek care from a professional cardiac clinic with experienced cardiologists and access to advanced diagnostic tools. A specialised cardiac clinic can provide accurate diagnoses, develop personalised treatment plans, and offer ongoing care to manage the condition effectively. Trusting a professional cardiac clinic ensures that patients receive the highest standard of care, which is critical for preventing complications, improving symptoms, and enhancing long-term outcomes.

In conclusion, diastolic dysfunction is a significant cardiac condition that requires careful monitoring and appropriate treatment. Understanding its symptoms, causes, and treatment options, along with the importance of professional care, is essential for managing the condition effectively and maintaining a better quality of life.