What Is Diastolic Filling?

The period of time when the heart muscle is relaxed and filling with blood returned to the heart after circulating through the body and the lungs is known as diastolic filling. Blood enters the heart through the superior vena cava, the pulmonary veins, and the inferior vena cava. Abnormal diastolic filling patterns may be a symptom of heart failure or pulmonary stenosis (PS).

Diastolic blood pressure readings measure the arterial pressure within the heart when the muscle is at its most relaxed during diastolic filling. The lowest measurement taken is the number recorded. On a typical blood pressure measurement, the diastolic pressure is the number on the bottom of the fraction. The other number is the systolic pressure, which is the highest measurement of atrial pressure, and is recorded as the top number of a blood pressure fraction.

The rate of diastolic filling has two measurements. Early diastolic reading (E) is measured when the blood that remains after the last heart muscle contraction flows into the heart. Atrial contraction (A) occurs next, and the fill rate is measured again. An E/A rate can be used to indicate cardiac dysfunction and the need for further testing.

Abnormal filling patterns may be a symptom of heart failure. People with moderate heart failure tend to have lower E and A measurements and long periods of cardiac muscle relaxation. Severe heart failure is marked by a short period of cardiac muscle relaxation and high E and A measurements.

Many people with pulmonary stenosis have abnormal diastolic filling patterns. Most have a decreased rate of filling during the E phase and an increased rate during the A phase. It is thought that muscle hypertrophy causes the abnormal filling pattern. Treatment for pulmonary valve stenosis is a surgical procedure to widen the pulmonary valve called balloon valvuloplasty.

The diastolic filling rate may be affected by a stiffening of the heart muscle. High blood pressure can cause the muscle on the left side of the heart to become stiff and unable to relax. Many people have scarred cardiac muscle after a myocardial infarction, or a heart attack. The scar tissue is unable to relax enough to allow proper filling velocity.

Some people with diabetes may have some stiff cardiac muscle that impairs diastolic filling. Elevated blood sugar levels can result in the glycosylation of the heart muscle. The excess sugar deposits in the muscle interfere with the relaxation of the tissue, resulting in abnormal filling rates.

Treatment for abnormal diastolic filling rates depends on the underlying condition causing the condition. Medications, including calcium channel blockers and angiotensin converting enzyme inhibitors, may help normalize filling velocity. Some people that also have pulmonary edema may need to take diuretics as part of the treatment program.