Do patients with suspected heart failure and preserved left ventricular systolic function suffer from “diastolic heart failure” or from misdiagnosis? A prospective descriptive study

EDITOR:

The paper by Caruana and colleagues does not demonstrate that
patients with suspected heart failure without left ventricular systolic
dysfunction are suffering from 'misdiagnosis' rather than diastolic heart
failure, as implied in their title.1

Firstly, patients studied were from a direct access echocardiography
service. Depending upon the design of the request form, the referring
clinician may have indicated 'suspected heart failure' for patients with a
wide range of pre-test probabilities that this was the predominant cause
of their symptoms.

Secondly, the mean ejection fraction by Simpson's biplane method was
45%, the cut-off point for inclusion in some studies of treatment for
systolic heart failure.2 Furthermore, 25% of patients had left
ventricular hypertrophy, and 67% had an E:A ratio of less than 1.0. These
are both indicators suggestive of diastolic dysfunction, although it is
accepted that no clear-cut non-invasive criteria exist for diagnosing this
condition.3

Thirdly, although obesity and lung disease were identified as non-
cardiac explanations for breathlessness, no attempt was made to evaluate
their importance in explaining clinical findings. Multiple pathology is
common in a breathless population whose mean age is 71 years, and no
comparator group with left ventricular systolic dysfunction was studied.

Caruana and colleagues' paper rightly demonstrates the importance of
thorough evaluation to look for multiple causes of breathlessness in this
population (including patients with systolic heart failure), but provides
no evidence that diastolic dyfunction is a 'misdiagnosis'. We shall not
know the relevance of this condition until we have results of treatment
studies.

1. Caruana L, Petrie MC, Davie AP, McMurray JJ. Do patients with
suspected heart failure and preserved left ventricular systolic function
suffer from "diastolic heart failure" or from misdiagnosis? A prospective
descriptive study. BMJ 2000;321:215-8.

2. The digitalis investigation group. The effect of digoxin on
mortality and morbidity in patients with heart failure. N Engl.J Med
1997;336:525-33.

3. The Task Force on Heart Failure of the European Society of
Cardiology. Guidelines for the diagnosis of heart failure. Eur.Heart J
1995;16:741