What is the primary characteristic of diastolic dysfunction in heart failure?

The primary characteristic of diastolic dysfunction in heart failure is the abnormal filling and relaxation of the heart. In this condition, the heart's ventricles do not fill properly with blood during the diastolic phase, which is the time when the heart relaxes and fills with blood. This impairment in filling is often due to stiffness of the heart muscle or an inability of the heart to relax adequately.

As a result, the heart may struggle to accommodate the necessary volume of blood returning from the body, leading to increased pressure in the heart and pulmonary circulation. Over time, this can contribute to the symptoms often seen in heart failure, such as shortness of breath and edema. Understanding this characteristic is crucial for clinicians in diagnosing and managing patients with heart failure, particularly those with preserved ejection fraction where diastolic dysfunction is common.

The other options may be associated with heart failure but do not specifically capture the essence of diastolic dysfunction. For instance, increased blood pressure in the arteries may occur due to various cardiovascular issues but is not indicative of diastolic function specifically. Similarly, changes in heart rate and cardiac output during exercise are complications that can arise from various forms of heart failure, rather than defining characteristics of diastolic dysfunction itself