What Is Diastolic Dysfunction and Diastolic Heart Failure?

Diastolic dysfunction is a cardiac condition caused by a “stiffening” of the heart’s ventricles (the major pumping chambers). This relative stiffness restricts the heart’s ability to fill up with blood in between heart beats. 

While diastolic dysfunction itself often causes no real symptoms, if it progresses far enough diastolic heart failure can occur. Diastolic heart failure, like any kind of heart failure, is potentially quite dangerous.

The cardiac cycle is divided into two parts - systole and diastole. During systole, the ventricles (the heart's major pumping chambers) contract, thus ejecting blood out of the heart and into the arteries. After the ventricles have finished contracting, they relax, and during this relaxation they fill up with blood to prepare for the next systole. This relaxation phase of the cardiac cycle is called diastole.

Sometimes, due to various medical conditions, the ventricles begin to become relatively "stiff." Stiff ventricles are not able to fully relax during diastole; as a result, the ventricles may not fill completely. As a result of this incomplete filling of the ventricles, the amount of blood pumped with the subsequent heart beat will be slightly reduced. Also, the blood which is returning to the heart can partially "dam up" in the body's organs (mainly the lungs).

The abnormal stiffening of the ventricles and the resulting abnormal ventricular filling during diastole are referred to as diastolic dysfunction.

Diastolic dysfunction is very mild at first, and usually does not initially produce symptoms. However, diastolic dysfunction tends to progress over time. When the condition becomes is sufficiently advanced to produce pulmonary congestion (that is, a damming up of blood into the lungs), diastolic heart failure is said to be present.

In general, when doctors use the terms diastolic dysfunction and diastolic heart failure, they are referring to isolated diastolic abnormalities - there is diastolic dysfunction without any evidence of systolic dysfunction. ("Systolic dysfunction" is just another name for a weakening of the heart muscle, which occurs in the more typical forms of heart failure.)

Diastolic dysfunction and diastolic heart failure are relatively “new” cardiac diagnoses. They have always been around, of course, but only in the past three decades or so, since echocardiography has been widely used to diagnose heart problems, that these conditions have become commonly recognized.

The diagnosis of diastolic dysfunction is now made quite frequently, especially in people over 45 years of age, most of whom are shocked to hear they have a heart problem at all. While some of these people will go on to develop actual diastolic heart failure, many will not — especially if they get appropriate medical care and take care of themselves.

Similarly, diastolic heart failure is also diagnosed frequently today. Almost half the patients who come to emergency rooms with episodes of acute heart failure turn out to have diastolic heart failure.

People with diastolic dysfunction and diastolic heart failure are likely to be older (over 45), overweight or obese, hypertensive, female, and have no history of heart attacks. It is currently believed that the risk of developing diastolic dysfunction is the same in men and women, but that older men who are obese and have hypertension are more likely to have heart attacks than women of similar age — so their heart failure is more likely to be “standard” congestive heart failure than diastolic heart failure.

Several conditions seem to contribute to diastolic stiffening of the heart. These include:

• High blood pressure
• Hypertrophic cardiomyopathy
• Aortic stenosis
• Coronary artery disease
• Restrictive cardiomyopathy
• Diabetes
• Obesity
• Sleep disordered breathing
• Aging (Whether age itself causes stiffening of the ventricles, or whether such stiffening is related to some other medical condition associated with aging, is not yet understood.)

People with diastolic dysfunction usually have no overt symptoms from the condition. They may, however, notice a gradual decrease in exercise capacity (which they are likely to attribute to age and being overweight).

Once diastolic heart failure occurs, the chief symptom is dyspnea (shortness of breath), just as it is with congestive heart failure. However, in distinction to congestive heart failure (in which symptoms most typically build up gradually over hours or days), the dyspnea with diastolic heart failure is more likely to be quite sudden in onset, and can be very severe immediately. These episodes are commonly referred to as “flash pulmonary edema.”

Diastolic dysfunction and heart failure are diagnosed with echocardiography.

In people with diastolic dysfunction, the echocardiogram is evaluated for the characteristics of diastolic relaxation; in other words, for “stiffness.”

In people with diastolic heart failure, the echocardiogram shows diastolic stiffness along with normal systolic (pumping) function of the heart. Specifically, the left ventricular ejection fraction is normal in a person with heart failure. In fact, most cardiologists today prefer the term “heart failure with preserved ejection fraction,” or HFpEF, over the “older” term diastolic heart failure.

Read more about the symptoms and the diagnosis of diastolic heart failure and diastolic dysfunction.

Treating diastolic dysfunction is aimed at reducing its underlying causes. Losing weight, getting plenty of exercise, treating hypertension, keeping diabetes under control, and reducing the risk factors for coronary artery disease can all improve cardiac diastolic function.

Treating diastolic heart failure can present a challenge, because many of the drugs that are effective in treating congestive heart failure are of little or no benefit. When acute pulmonary edema is present, diuretics (such as Lasix) are the mainstay of therapy. As with anyone who has diastolic dysfunction, lifestyle changes and aggressive treatment of hypertension and diabetes are helpful in preventing recurrent episodes of heart failure. If atrial fibrillation has occurred, it is important to take steps to prevent recurrence of this arrhythmia, because it can trigger cardiac decompensation in people with diastolic heart failure.

Read more about the treatment of diastolic dysfunction and diastolic heart failure.