These are both severe forms of diastolic dysfunction, and patients tend to have advanced heart failure symptoms:
Class III diastolic dysfunction patients will demonstrate reversal of their diastolic abnormalities on echocardiogram when they perform the Valsalva maneuver. This is referred to as "reversible restrictive diastolic dysfunction". Class IV diastolic dysfunction patients will not demonstrate reversibility of their echocardiogram abnormalities, and are therefore said to have "fixed restrictive diastolic dysfunction".The presence of either class III and IV diastolic dysfunction is associated with a significantly worse prognosis. These patients will have left atrial enlargement, and many will have a reduced left ventricular ejection fraction that indicates a combination of systolic and diastolic dysfunction.Imaged volumetric definition of systolic heart performance is commonly accepted as ejection fraction. Volumetric definition of the heart in systole was first described by Adolph Fick as cardiac output. Fick may be readily and inexpensively inverted to cardiac output and ejection fraction to mathematically describe diastole. Decline of ejection fraction paired with decline of E/A ratio seems a stronger argument in support of a mathematical definition of diastolic heart failure.Another parameter to assess diastolic function is the E/E ratio, which is the ratio of mitral peak velocity of early filling (E) to early diastolic mitral annular velocity (E). Diastolic dysfunction is assumed when the E/E ratio exceed 15.Newer echocardiographic techniques such as speckle tracking for strain measurement, particularly for the left atrium, are becoming increasingly utilised for the diagnosis of HFpEF. Treatment
Despite increasing incidence of HFpEF effective inroads to therapeutics have been largely unsuccessful.
While therapies for dyssynchrony, such as biventricular pacing provide benefits to HFrEF patients, no benefit is appreciable in HFpEF patients at this time. Systemic abnormalities
Patients with HFpEF, in addition to cardiac abnormalities, display changes in (endothelial) microvascular function, skeletal muscle metabolism and in fat distribution and character throughout the body. The importance of these changes is demonstrated in that stable, non-decompensated patients seem to benefit from exercise; specifically increased VO2 max and exercise tolerance. However, this benefit appears to be derived from changes in muscle and vasculature as opposed to directly on the heart, which displays minimal change in output following exercise training. Diagnosis
HFpEF is typically diagnosed with echocardiography. Techniques such as catheterization are invasive procedures and thus reserved for patients with co-morbid conditions or those who are suspected to have HFpEF but lack clear non-invasive findings. Catheterization does represent are more definitive diagnostic assessment as pressure and volume measurements are taken simultaneously and directly. In either technique, the heart is evaluated for left ventricular diastolic function. Important parameters include, rate of isovolumic relaxation, rate of ventricular filling, and stiffness.Frequently patients are subjected to stress echocardiography, which involves the above assessment of diastolic function during exercise. This is undertaken because perturbations in diastole are exaggerated during the increased demands of exercise. Exercise requires increased left ventricular filling and subsequent output. Typically the heart responds by increasing heart rate and relaxation time. However, in patients with HFpEF both responses are diminished due to increased ventricular stiffness.