Diastolic Heart Failure: Causes, Symptoms, Diagnosis, Treatment and Prevention

Diastolic Heart Failure: Causes, Symptoms, Diagnosis and Treatment

~Introduction

Diastolic heart failure, also known as Heart Failure with Preserved Ejection Fraction (HFpEF), is a form of heart failure in which the heart’s left ventricle becomes stiff and cannot relax properly between beats. Although the heart pumps normally (ejection fraction is preserved), it struggles to fill adequately with blood during diastole, leading to congestion in the lungs and other tissues.

In recent years, diastolic heart failure has gained increasing attention among clinicians because it accounts for nearly half of all heart failure cases worldwide. The condition is particularly common in older adults, women, and people with hypertension, obesity, or diabetes. Understanding diastolic heart failure is essential for early recognition, effective management, and prevention of complications that can severely impact quality of life.

~Understanding Diastolic Function

To appreciate diastolic heart failure, it is crucial to understand how the heart functions during its pumping cycle.

• Systole refers to the phase when the heart contracts and pumps blood out of the ventricles.

• Diastole is the phase when the ventricles relax and fill with blood returning from the body (right side) and the lungs (left side).

In a healthy heart, the ventricles relax easily, allowing adequate filling with blood. In diastolic heart failure, however, the ventricular walls become stiff or thickened, making it difficult for the heart to fill properly without increasing pressure. This leads to a backflow of pressure into the lungs and veins, causing symptoms of congestion such as shortness of breath and fatigue.

~Difference Between Diastolic and Systolic Heart Failure

Heart failure is broadly classified into two types based on the ejection fraction (EF) — the percentage of blood pumped out of the ventricle with each contraction:

Type of Heart Failure	Ejection Fraction	Main Problem
Systolic Heart Failure (HFrEF)	<40%	The heart cannot contract strongly enough to eject blood efficiently.
Diastolic Heart Failure (HFpEF)	≥50%	The heart contracts normally but cannot relax and fill properly.

In systolic failure, the heart is weak; in diastolic failure, the heart is stiff. However, both conditions ultimately result in inadequate cardiac output and symptoms of congestion.

~Causes and Risk Factors

Diastolic heart failure develops due to conditions that alter the structure or function of the left ventricle, impairing its ability to relax. Common causes and risk factors include:

1. Hypertension

Chronic high blood pressure is the most common cause. Over time, increased pressure causes the heart muscle to thicken (left ventricular hypertrophy), making it less compliant and harder to fill.

2. Coronary Artery Disease

Reduced blood flow to the heart muscle due to atherosclerosis can cause scarring and stiffness, leading to diastolic dysfunction.

3. Aging

As people age, the myocardium naturally becomes less elastic. This age-related stiffening increases susceptibility to HFpEF, especially in older women.

4. Diabetes Mellitus

Diabetes can damage blood vessels and promote fibrosis (scarring) of the heart muscle, contributing to diastolic dysfunction.

5. Obesity

Excess body weight increases cardiac workload and leads to structural changes in the heart, predisposing to HFpEF.

6. Atrial Fibrillation

Irregular atrial contractions impair ventricular filling and worsen diastolic pressure.

7. Valvular Heart Disease

Aortic stenosis or mitral valve disease can elevate left ventricular pressures and contribute to stiffening.

8. Restrictive Cardiomyopathy

Diseases that infiltrate the heart muscle, such as amyloidosis or sarcoidosis, can make the heart walls rigid and noncompliant.

~Pathophysiology

In diastolic heart failure, the primary abnormality lies in the relaxation phase of the cardiac cycle. During diastole, the ventricle must relax to allow blood to enter. If the ventricle becomes stiff, the filling pressure increases, and less blood enters despite a normal ejection fraction.

This elevated filling pressure is transmitted backward into the left atrium and pulmonary veins, causing pulmonary congestion and symptoms like shortness of breath, especially during exertion or at night.

Over time, these changes trigger a cascade of compensatory mechanisms involving the renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system, which can further worsen stiffness, sodium retention, and vascular resistance.

~Symptoms of Diastolic Heart Failure

The symptoms of diastolic heart failure often resemble those of other forms of heart failure. They usually develop gradually and worsen over time.

Common Symptoms Include:

• Shortness of breath (dyspnea): Especially during physical activity or when lying flat.

• Fatigue and weakness: Due to reduced oxygen delivery to tissues.

• Swelling (edema): Especially in the ankles, legs, or abdomen.

• Rapid weight gain: From fluid retention.

• Frequent urination at night (nocturia).

• Palpitations or irregular heartbeat.

• Coughing or wheezing: Caused by fluid buildup in the lungs.

Because symptoms often overlap with other conditions like lung disease or obesity, diastolic heart failure can be challenging to diagnose early.

~Stages of Diastolic Heart Failure

The American College of Cardiology (ACC) and American Heart Association (AHA) classify heart failure progression into four stages:

1. Stage A: At risk but without symptoms (e.g., hypertension, diabetes).

2. Stage B: Structural heart changes but no symptoms.

3. Stage C: Structural heart disease with current or past symptoms.

4. Stage D: Advanced or refractory heart failure requiring specialized interventions.

Most patients with HFpEF are diagnosed in Stage C, when symptoms become apparent.

~Diagnosis

Diagnosing diastolic heart failure requires a combination of clinical evaluation, imaging tests, and laboratory investigations.

1. Medical History and Physical Examination

A doctor assesses symptoms such as dyspnea, fatigue, and swelling, as well as risk factors like hypertension or diabetes. Physical examination may reveal:

• Elevated jugular venous pressure

• Crackles in the lungs

• Peripheral edema

• An S4 heart sound (due to stiff ventricle)

2. Echocardiogram

This is the most important diagnostic tool. It measures:

• Ejection fraction (typically ≥50% in HFpEF)

• Left ventricular wall thickness and relaxation patterns

• Left atrial size

• Diastolic filling pressures

Doppler echocardiography can assess the velocity of blood flow across heart valves to evaluate diastolic function.

3. B-type Natriuretic Peptide (BNP) or NT-proBNP Levels

Elevated BNP levels indicate heart failure and help distinguish cardiac from pulmonary causes of breathlessness.

4. Electrocardiogram (ECG)

Identifies arrhythmias (such as atrial fibrillation) and evidence of hypertrophy or ischemia.

5. Chest X-ray

May show pulmonary congestion or cardiomegaly.

6. Cardiac MRI

Provides detailed images of cardiac structure and function, especially useful for identifying infiltrative cardiomyopathies.

~Treatment and Management

There is no single curative treatment for diastolic heart failure. The goal is to control symptoms, manage underlying conditions, and prevent hospitalizations.

1. Lifestyle Modifications

Lifestyle changes are fundamental in managing HFpEF:

• Control blood pressure: Maintain target BP <130/80 mmHg.

• Limit salt intake: Helps prevent fluid retention.

• Maintain healthy body weight: Obesity worsens diastolic dysfunction.

• Exercise regularly: Moderate aerobic activity improves endurance and cardiac efficiency.

• Avoid alcohol and smoking: Both increase cardiac stress.

• Monitor daily weight: Sudden weight gain may indicate fluid accumulation.

2. Medications

Although no drugs specifically reverse diastolic dysfunction, several classes of medications help manage symptoms and comorbidities:

• Diuretics: Reduce fluid overload and relieve congestion.

• ACE inhibitors or ARBs: Improve blood pressure control and ventricular compliance.

• Beta-blockers: Slow the heart rate, allowing more time for ventricular filling.

• Mineralocorticoid receptor antagonists (e.g., spironolactone): May improve outcomes in some patients.

• SGLT2 inhibitors (dapagliflozin, empagliflozin): Recently shown to reduce hospitalization risk in HFpEF.

• Calcium channel blockers: Useful in managing hypertension and improving relaxation.

3. Management of Comorbidities

Since diastolic heart failure often coexists with other conditions, addressing these is crucial:

• Control diabetes: Maintain HbA1c <7%.

• Treat sleep apnea: Continuous positive airway pressure (CPAP) may reduce symptoms.

• Manage atrial fibrillation: Use rate or rhythm control and anticoagulation as indicated.

• Treat coronary artery disease: Revascularization may improve myocardial relaxation.

4. Advanced Therapies

In refractory cases, patients may need:

• Cardiac resynchronization therapy (CRT) in selected individuals with conduction abnormalities.

• Heart transplantation (rarely, in end-stage disease).

~Complications

Untreated or poorly managed diastolic heart failure can lead to serious complications, including:

• Pulmonary hypertension

• Right-sided heart failure

• Atrial fibrillation and stroke

• Chronic kidney disease

• Recurrent hospitalizations and reduced lifespan

~Prognosis

Although the ejection fraction remains normal, diastolic heart failure is not a benign condition. Mortality and hospitalization rates are comparable to those seen in systolic heart failure. Prognosis largely depends on:

• Age and sex (worse in elderly women)

• Presence of comorbidities

• Degree of blood pressure control

• Adherence to treatment and lifestyle changes

Early diagnosis and aggressive management can significantly improve outcomes and quality of life.

~Prevention

Prevention focuses on minimizing risk factors and maintaining cardiovascular health:

• Regular blood pressure checks

• Balanced diet rich in fruits, vegetables, and lean proteins

• Exercise at least 150 minutes per week

• Control of blood sugar and cholesterol

• Routine cardiac evaluations for high-risk individuals

~Recent Research and Advances

Recent studies have identified SGLT2 inhibitors as a promising treatment option for HFpEF. Trials like EMPEROR-Preserved and DELIVER demonstrated that drugs such as empagliflozin and dapagliflozin reduce hospitalization rates in HFpEF patients.

Additionally, novel biomarkers and advanced imaging techniques are being explored to detect diastolic dysfunction earlier and personalize therapy.

~Conclusion

Diastolic heart failure, or heart failure with preserved ejection fraction, is a growing global health concern, particularly in aging populations. Although the heart’s pumping function remains normal, impaired relaxation and stiffness lead to elevated filling pressures, congestion, and symptoms of heart failure.

Management focuses on controlling risk factors like hypertension, diabetes, and obesity, along with lifestyle changes and symptom relief. Early recognition, adherence to therapy, and regular follow-up can greatly improve prognosis. With ongoing research and emerging treatments, the outlook for patients with diastolic heart failure continues to evolve toward better outcomes and enhanced quality of life.