Chicago, IL - At one time, almost any heart failure in a patient with a normal LV ejection fraction was thought to be caused by impaired diastolic function, and the term "diastolic" HF became a popular way to distinguish the condition from reduced-ejection-fraction "systolic" HF. But the landscape of heart failure is more complex than that. A study of HF patients in the community, published in the November 8, 2006 Journal of the American Medical Association, illustrates just what a frontier it is [1].

In an analysis that integrated clinical and echocardiographic findings from 556 prospectively identified HF patients, 55% were found to have preserved LV systolic function, defined as an LVEF >50%. Far more, about 80%, had some degree of diastolic dysfunction. But the patients with reduced LV systolic function, or an LVEF <50%, were significantly more likely than those with higher ejection fractions to have moderate to severe diastolic dysfunction, according to the study, by Dr Francesca Bursi (University of Modena, Italy) and associates.

According to coauthor Dr Véronique L Roger (Mayo Clinic, Rochester, MN), the study suggests that diastolic dysfunction is very common in HF and drives home the point that LVEF by itself isn't the most useful way to characterize patients with the syndrome. "To accurately classify patients with heart failure, you would need to measure both ejection fraction and diastolic function with Doppler echocardiography," she told heartwire.

Participants in the study were prospectively recruited from her center's home county and so closely reflect the makeup of the broad HF population in the US, Roger observed, with the major exception that African Americans were underrepresented.

The analysis "underscores the importance of conducting Doppler echocardiographic studies in all patients with heart failure," according to Roger. That would help in directing interventions for diastolic-dysfunction risk factors, such as hypertension, obesity, and diabetes, at HF patients who might most benefit. Measurement of diastolic function isn't usually a part of their echocardiographic workup, she said, but it should be. "It's only when we start doing this that we're going to be able to understand what heart failure is."

The majority with preserved LV systolic function were, consistent with other studies, significantly older, more likely female, and had a more favorable average NYHA functional classification. Diastolic dysfunction predominated in both the reduced- and preserved-LVEF groups. But the odds ratio for moderate to severe diastolic dysfunction in reduced-LVEF patients was 1.67 (p=0.01) compared with those with preserved LVEF. Of the entire cohort, 44% had both a preserved LVEF and diastolic dysfunction.

Distributions of normal and mildly to severely impaired diastolic function did not change significantly in a similar analysis that was restricted to patients with HF as defined by the standard Framingham criteria or when an LVEF of 55% was used as the cut point for reduced vs preserved LVEF, the authors reported.

Levels of brain-type natriuretic peptide (BNP) were significantly increased in reduced-LVEF patients compared with those with preserved systolic function and, regardless of LVEF, were inversely related to the degree of diastolic dysfunction.

Any differences between reduced- and preserved-LVEF patients apparently didn't influence outcomes. Their associated six-month mortalities were the same at 16% and remained similar after adjustment for demographic and clinical features.

In an accompanying editorial, Dr Per Hildebrandt (Roskilde Hospital, Denmark) notes that the six-month mortality figure for the preserved-LVEF group is somewhat higher than what has been observed in other studies, few of which have focused on unselected populations [2]. "Just as heart failure with reduced LVEF has long been recognized as a common and serious disease and has been the subject of a number of large-scale clinical trials, the entities of heart failure with preserved LVEF and diastolic dysfunction equally deserve attention," he writes.

Roger said some clinicians may not want to start measuring diastolic function in their HF patients because they believe it would be an overly challenging or cumbersome addition to the traditional echocardiographic workup. "The algorithm that we propose, which we have extensive experience with, is something that can be added to an echocardiographic study without adding a lot of time and that really can be mastered by any dedicated team of providers," she said. Their process and criteria for the evaluation are outlined in the group's report. "It would be relatively easy to use in routine practice because it really requires only two sets of Doppler recordings."