Heart failure occurs when the heart muscle cannot pump blood efficiently enough to meet the body’s needs for oxygen and nutrients. When this condition persists, it is called chronic heart failure. Chronic Diastolic Heart Failure (DHF) is a distinct form where the problem is a filling issue, not a weak pump. DHF is defined by the heart’s difficulty relaxing and filling with blood between beats, which prevents it from adequately preparing for the next pump cycle.
Understanding Diastolic Dysfunction
The heart’s function is divided into two phases: systole and diastole. Systole is the contraction phase, where the heart actively pumps blood out to the body and lungs. Diastole is the relaxation phase, where the heart chambers, particularly the left ventricle, expand and fill with blood returning from circulation.
In chronic diastolic heart failure, the heart muscle, typically the left ventricle, becomes thickened and stiff. This stiffness prevents the ventricle from fully relaxing during diastole, making it resistant to incoming blood. Because the ventricle cannot easily expand, it cannot take in the necessary volume of blood.
When the ventricle cannot properly expand, it cannot fill with enough blood, which raises the pressure inside the heart chamber. This elevated pressure backs up into the left atrium and subsequently into the blood vessels of the lungs. This inadequate filling mechanism, rather than insufficient squeezing, causes the symptoms of heart failure.
This type of heart failure is often medically referred to as Heart Failure with Preserved Ejection Fraction (HFpEF). The term “preserved ejection fraction” means the percentage of blood the heart pumps out with each beat appears normal. While the heart’s contraction strength is maintained, the total volume of blood pumped is reduced because the ventricle could not fill adequately.
Common Signs and Symptoms
The difficulty in filling the heart and the resulting pressure backup cause several noticeable physical manifestations. A primary symptom is shortness of breath, which often first appears during physical exertion. As the condition progresses, breathlessness can occur even when the person is resting, or when lying flat, a symptom known as orthopnea.
This breathlessness occurs because the increased pressure in the heart pushes fluid backward, causing congestion and accumulation within the lungs. Persistent fatigue and generalized weakness are also common. These result from the reduced amount of blood sent to the body’s tissues, meaning muscles and organs do not receive sufficient oxygen and nutrients.
The backup of fluid can also lead to edema, or swelling, most commonly seen in the lower extremities like the legs, ankles, and feet. Fluid congestion can also affect the abdomen, causing swelling and sometimes leading to a loss of appetite. Other signs include a persistent cough or wheezing, sometimes with white or pink-tinged phlegm, due to fluid in the lungs.
Identifying the Underlying Causes
The development of chronic diastolic heart failure is linked to long-term conditions that place chronic stress on the heart muscle. The most common cause is uncontrolled high blood pressure, or hypertension. Over years, the heart works against this consistently high pressure, causing the muscle of the left ventricle to thicken and stiffen, a process called hypertrophy.
Aging itself is a contributing factor, as the heart and blood vessels naturally lose elasticity and become less compliant over time. Several widespread metabolic conditions also significantly increase risk. Diabetes can lead to specific changes in the heart muscle cells and surrounding tissue, promoting stiffness and fibrosis.
Obesity is another prominent risk factor, as the increased body mass forces the heart to work harder to supply blood to a larger volume of tissue. These underlying health issues collectively cause chronic inflammation and stress, ultimately leading to the structural changes in the heart that define diastolic heart failure.
Diagnosis and Management Strategies
Diagnosis of chronic diastolic heart failure begins with a physical examination and a review of the patient’s symptoms, especially those related to fluid buildup and breathlessness. Specialized tests are then used to confirm the diagnosis and distinguish it from other forms of heart failure. Echocardiography, a non-invasive ultrasound of the heart, is a primary tool used to visualize the heart’s structure and function.
This imaging allows clinicians to measure the preserved ejection fraction and assess signs of diastolic dysfunction, such as impaired relaxation and elevated filling pressures. Blood tests, specifically measuring B-type natriuretic peptide (BNP) levels, also support the diagnosis, as high levels of this hormone are released when the heart muscle is under stress.
Management of DHF focuses on controlling the underlying causes and alleviating the symptoms caused by fluid retention. A primary strategy is aggressive control of blood pressure to reduce the stress on the heart muscle. Medications often include “water pills,” or diuretics, which help the body eliminate excess fluid, thereby reducing lung congestion and peripheral swelling.
Lifestyle modifications are also encouraged, including dietary changes focused on reducing sodium intake to minimize fluid retention. Regular physical activity and weight management are important components of treatment. The goal of this combined approach is to improve the heart’s ability to fill and relax, managing symptoms and improving quality of life.