Diastolic heart failure.

to the editor: Zile et al. (May 6 issue) 1 conclude that heart failure develops in patients with a normal ejection fraction because of abnormal active and passive diastolic function. However, the applicability of this conclusion to all such patients is uncertain for several reasons. First, accurate assessment of left ventricular volume, on which the conclusions critically depend, requires a three-dimensional imaging technique that measures the long axis 2,3 ; two-dimensional techniques are inadequate for this purpose. Second, the majority of the patients studied were men, and on average, they were less than 60 years of age. However, most patients with a normal ejection fraction in whom heart failure develops are elderly women. 4 Third, although the underlying disease in patients with heart failure and a normal ejection fraction differs according to whether hypertension is or is not present, data from these two groups were pooled, precluding the identification of different pathophysiological mechanisms. Fourth, the results do not account for data already in the literature showing that there are rightward, downward shifts of the diastolic pressure–volume relation in some patients with heart failure and a normal ejection fraction. 5 Therefore, the conclusions reached by Zile et al. may not apply to most patients with heart failure and a normal ejection fraction. The mechanisms responsible for this disorder in most patients still need to be elucidated.