Diastolic Dysfunction and Heart Failure

Diastolic dysfunction refers to the inability of the heart muscle to relax normally after each heartbeat. Since it is during this relaxation phase (referred to as "diastole") that the cardiac ventricles (the main pumping chambers) fill with blood in preparation for the next heartbeat, diastolic dysfunction can impair cardiac filling.

This impaired filling can restrict the amount of blood the heart can pump with each heartbeat and can increase the pressures within the heart. Severe diastolic dysfunction can lead to diastolic heart failure, too.

Diastolic dysfunction itself most often produces no symptoms at all. A general, gradually progressive decrease in exercise tolerance may occur. However, many people with diastolic dysfunction do not notice this symptom either because they lead relatively sedentary lives (which is one of the risk factors for diastolic dysfunction) or they subconsciously reduce their exercise to compensate for their decreasing capacity to exert themselves.

But, when diastolic heart failure sets in, significant symptoms are common. While the symptoms that occur with diastolic heart failure are similar to symptoms people experience who have any other form of heart failure, pulmonary symptoms—caused by lung congestion—are often especially prominent in those with diastolic heart failure.

Severe dyspnea (breathlessness), often accompanied by coughing and rapid breathing, is the typical manifestation of diastolic heart failure. Furthermore, symptoms often may be experienced in discrete episodes which may occur quite suddenly and without any warning.

This type of sudden onset is quite different from the pattern typically seen in people with "usual" kinds of heart failure in which the onset of dyspnea tends to be gradual, occurring over a period of hours or days. The sudden, severe breathing difficulties common with diastolic heart failure are referred to as episodes of "flash pulmonary edema."

These episodes of flash pulmonary edema can be triggered by other medical conditions, including atrial fibrillation and other types of tachycardia (rapid heart rhythms), periods of hypertension (high blood pressure, especially systolic blood pressure elevations), and episodes of cardiac ischemia.

Each of these medical conditions can cause a further deterioration in the heart's diastolic function and can push a person with significant diastolic dysfunction over the edge. Also, while episodes of flash pulmonary edema are considered a hallmark of diastolic heart failure, people with this condition can often experience less severe and more gradual onsets of dyspnea.

Diastolic heart failure is diagnosed when a person has an episode of heart failure and subsequent evaluation shows that the systolic function of the heart (that is, its ability to eject blood with a strong pumping action) is normal.

To say it another way, they have heart failure despite having a normal left ventricular ejection fraction. In recent years cardiologists have recognized that up to 50 percent of people who seek medical help for episodes of acute pulmonary congestion turn out to have diastolic heart failure.

Diastolic dysfunction can be diagnosed by an echocardiogram, which can assess the characteristics of diastolic relaxation and the degree of left ventricular "stiffness." The echocardiogram can sometimes also reveal the cause of diastolic dysfunction in certain people.

For instance, the echocardiogram can reveal the thickened left ventricular muscle (that is, ventricular hypertrophy) associated with hypertension and hypertrophic cardiomyopathy. It can also reveal the presence of aortic stenosis or of restrictive cardiomyopathies. (All of these conditions can produce diastolic dysfunction.)

However, in many people with diastolic dysfunction, echocardiography will show no other abnormalities to explain why the condition is present. In these patients, it is not possible to attribute a specific cause to the diastolic dysfunction.

Diastolic dysfunction is far more common than cardiologists used to think. Some echocardiographic studies have detected diastolic dysfunction in 15 percent of individuals under 50 years old and in as many as 50 percent of people over 70.

Diastolic dysfunction is largely a disorder of women, too. Up to 75 percent of people diagnosed with diastolic heart failure are female.

Diastolic heart failure is diagnosed when a person with diastolic dysfunction develops an episode of pulmonary congestion severe enough to produce symptoms. If an episode of diastolic heart failure occurs once, it is extremely likely to happen again, especially if treatment is suboptimal.

In recent years, cardiologists have come to recognize the significance of diastolic dysfunction and that it is a far more prevalent condition than previously realized. It is extremely important for anyone with diastolic dysfunction to take this condition very seriously and to work with their doctors to devise the optimal strategy for achieving a good and healthy outcome.