Diastolic failure is a form of heart failure where the heart struggles to relax and fill with blood. Unlike other types of heart failure where the pumping action is weakened, in diastolic failure, the heart’s ability to properly relax between beats is impaired. This means the heart cannot adequately fill its chambers with blood, which in turn affects the amount of blood it can pump out to the body. The issue lies not in the heart’s strength to contract, but in its flexibility to expand and receive blood.
Understanding the Heart’s Role in Diastolic Failure
The heart operates through a rhythmic cycle of contraction and relaxation, known as the cardiac cycle. Systole refers to the phase when the heart muscle contracts, ejecting blood into the arteries. Conversely, diastole is the phase when the heart muscle relaxes, allowing the chambers to fill with blood in preparation for the next contraction. A healthy heart efficiently transitions between these two states, ensuring a continuous and adequate supply of blood to the body.
In diastolic failure, the left ventricle, the heart’s main pumping chamber, becomes abnormally stiff and thick. This stiffness prevents the ventricle from fully relaxing and expanding during diastole. Consequently, the ventricle cannot adequately draw blood from the lungs. This impaired filling increases pressure within the heart chambers and the blood vessels leading to the heart.
The elevated pressures can then back up into the lungs, leading to fluid accumulation. Over time, this chronic underfilling and increased pressure can strain the heart and other organ systems.
Causes and Risk Factors
Chronic high blood pressure (hypertension) is a primary contributor to diastolic failure. Sustained high pressure forces the heart to work harder, leading to thickening and stiffening of the left ventricle over many years. This makes the heart muscle less able to relax fully during diastole.
Diabetes is another significant risk factor, as high blood sugar levels can damage blood vessels and heart muscle over time. This damage can contribute to heart tissue stiffening, impairing its ability to relax and fill. Obesity also plays a role, often linked to hypertension and diabetes. It can directly contribute to heart stiffness and ventricular thickening by increasing the heart’s workload.
The natural aging process also contributes to risk. As people age, heart muscle fibers become less elastic and more rigid. This stiffening reduces the heart’s ability to relax and fill efficiently. These underlying conditions collectively contribute to progressive changes in heart structure and function characteristic of diastolic failure.
Recognizing Symptoms and Diagnosis
Individuals with diastolic failure often experience symptoms related to the heart’s inability to effectively fill and manage fluid. Shortness of breath is a common complaint, particularly with physical exertion or when lying flat, as fluid can accumulate in the lungs due to increased pressure backing up from the heart. Fatigue may also occur because the body’s tissues are not receiving enough oxygen-rich blood, even though the heart’s pumping strength may appear normal. Swelling in the legs, ankles, or abdomen can develop as increased pressure in the veins leads to fluid leaking into surrounding tissues.
Diagnosing diastolic failure involves a combination of clinical evaluation and specific tests. An echocardiogram is a primary diagnostic tool, using sound waves to create images of the heart. This test allows doctors to assess the heart’s relaxation and filling patterns, measure the thickness of the heart muscle, and determine the ejection fraction. The ejection fraction indicates the percentage of blood pumped out with each beat; in diastolic failure, this value is often preserved or near normal, which helps distinguish it from other types of heart failure.
An electrocardiogram (EKG) records the heart’s electrical activity and can reveal signs of heart muscle thickening or rhythm abnormalities. Blood tests, such as those measuring B-type natriuretic peptide (BNP) levels, can also provide supporting evidence. Elevated BNP levels often indicate increased pressure within the heart, suggesting heart strain.
Distinguishing HFpEF from HFrEF
Diastolic heart failure is often termed Heart Failure with Preserved Ejection Fraction (HFpEF). In HFpEF, the heart’s ability to pump blood out (ejection fraction) remains largely intact, while the problem lies in its relaxation and filling. In contrast, systolic heart failure (Heart Failure with Reduced Ejection Fraction or HFrEF) involves a weakened pumping ability and a reduced ejection fraction.
Treatment and Living with Diastolic Failure
Managing diastolic failure primarily focuses on addressing underlying conditions and alleviating symptoms. Lifestyle modifications play a significant role in improving outcomes.
Lifestyle Modifications
Reducing sodium intake to minimize fluid retention and decrease the workload on the heart.
Engaging in regular, moderate exercise, tailored to individual capabilities, to improve cardiovascular fitness and overall well-being.
Maintaining a healthy weight.
Stopping smoking, as it reduces strain on the heart and improves its function.
Medications are often prescribed to manage the condition and its symptoms. Diuretics, sometimes called “water pills,” help reduce fluid buildup in the body, which can lessen shortness of breath and swelling. Medications to control blood pressure, such as ACE inhibitors, ARBs, or beta-blockers, are frequently used to lower the heart’s workload and prevent further stiffening. Managing conditions like diabetes with appropriate medications is also important to slow the progression of heart damage.
Uncontrolled diastolic failure can lead to several complications, including chronic kidney disease due to reduced blood flow, and atrial fibrillation, an irregular heart rhythm that can further impair the heart’s filling. While diastolic failure is a chronic condition, proper management can significantly improve the quality of life and slow its progression.