The epidemiological enigma of heart failure with preserved systolic function.

Background: Current epidemiological evidence suggests that the prevalence of preserved systolic function in patients with heart failure varies widely from 13 to 74%. This inconsistency suggests a lack of consensus as to what this condition really is and how it has been characterised for epidemiological studies. Aims: In this review, we summarise and discuss the current understanding of the epidemiology of heart failure with preserved systolic function and the challenges that this raises. Methods: Studies were identified from Medline and Embase Literature Database searches using the subject headings heart failure, diastolic heart failure, epidemiology, incidence, prevalence, diagnosis, prognosis and mortality. Results: Sixty-one studies of congestive heart failure with preserved systolic function were reviewed. There is great diversity in the criteria used to determine whether heart failure is present, the patient population, the setting of the study and methods of evaluating left ventricular function. This makes epidemiological studies of prevalence, morbidity and mortality impossible to compare. Conclusions: The diagnosis of this syndrome might be better defined in terms of symptoms, elevated neuro hormones and impaired cardiac workload. This would allow accurate identification of cases so that further research could be conducted to measure outcome and assess therapeutic benefit. (C) 2003 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.