Elsevier

The Lancet

Volume 350, Issue 9081, 20 September 1997, Pages 829-833
The Lancet

Articles
Symptomatic and asymptomatic left-ventricular systolic dysfunction in an urban population

https://doi.org/10.1016/S0140-6736(97)03033-XGet rights and content

Summary

Background

In most previous epidemiological studies on the prevalence of chronic heart failure (CHF) the disorder has been defined on clinical criteria. In a cross-sectional survey of 2000 men and women aged 25–74, randomly sampled from one geographical area, we assessed left- ventricular systolic function by echocardiography.

Methods

1640 (83%) of those invited took part. They completed a questionnaire on current medication, history, and symptoms of breathlessness. Blood pressure was measured and electrocardiography (ECG) and echocardiography were done. Left-ventricular ejection fraction was measurable in 1467 (89·5%) participants by the biplane Simpson's rate method.

Findings

The mean left-ventricular ejection fraction was 47·3%. The prevalence of definite left-ventricular systolic dysfunction (defined as a left-ventricular ejection fraction ≤30%) was 2·9% overall (43 participants); it increased with age and was higher in men than in women (4·0 vs 2·0%). The left-ventricular systolic dysfunction was symptomatic in 1·5% of participants and asymptomatic in 1·4%. 83% of participants with left-ventricular systolic dysfunction had evidence of ischaemic heart disease (IHD) from history or ECG criteria compared with 21% of those without this abnormality (p<0·001). Hypertension was also more common in those with left-ventricular systolic dysfunction (72 vs 38%, p<0·001), but there was no difference between those with and without left-ventricular systolic dysfunction in the rate of hypertension without IHD.

Interpretation

Left-ventricular systolic dysfunction was at least twice as common as symptomatic heart failure defined by clinical criteria. The main risk factors are IHD and hypertension in the presence of IHD; screening of such high-risk groups for left-ventricular systolic dysfunction should be considered.

Introduction

Despite the falling trend for other cardiovascular disorders, the incidence and prevalence of chronic heart failure (CHF) are predicted to rise substantially over the next 10 years.1 Already, increasing rates of hospital admission for CHF have been reported from Europe and the USA,2, 3, 4 and the disorder now accounts for 1–2% of all health-care expenditure.5

In developed countries CHF is mainly attributable to left-ventricular systolic dysfunction (although some patients have diastolic dysfunction). The substantial morbidity and mortality6, 7, 8 can be greatly reduced by appropriate treatment.8, 9 Moreover, treatment at the asymptomatic stage can delay or prevent progression to symptomatic left-ventricular systolic dysfunction and its consequences.10, 11

Little is known, however, about the epidemiology of CHF and less still about its probable precursor, asymptomatic left-ventricular systolic dysfunction. Most population surveys have relied on a clinical diagnosis of CHF.5, 12, 13 However, Wheeldon and colleagues14 found that many patients with a diagnosis of CHF do not have left-ventricular systolic dysfunction or, indeed, any significant cardiac abnormality. In addition, previous population surveys have been unable to identify people with asymptomatic left-ventricular systolic dysfunction.

We report a large-scale epidemiological study that used two-dimensional echocardiography to investigate the prevalence and predictors of both symptomatic and asymptomatic left-ventricular systolic dysfunction in men and women aged 25–74 years, randomly sampled from a geographically defined urban population.

Section snippets

Methods

All 2000 people (200 men, 200 women, in each 10-year age band from 25 to 74 years) who had attended the third Glasgow MONICA coronary-risk-factor survey in 1992 (response rate 67%)15, 16 were invited to take part in this study; 1640 reattended (response rate 83%). This sample is representative of the original cohort in all relevant criteria, except that the attenders were more affluent and there were fewer smokers. The frequencies of coronary heart disease and hypertension were the same as

Results

The ejection fraction was measurable in 1467 (89·5%) of the 1640 participants; the proportion with measurable ejection fractions ranged from 86·2% in men aged 65–74 to 94·8% in women aged 25·34. Participants with measurable ejection fractions were significantly younger than those without a measurement, lower proportions had diabetes and hypertension, and the mean body-mass index was lower. The difference in the proportion with angina almost reached significance (table 1).

Left-ventricular

Discussion

In this first study of symptomatic and asymptomatic left-ventricular systolic dysfunction in the general population, we found that a low ejection fraction is common; 2·9% of the population had definite left-ventricular systolic dysfunction, of whom about 50% were asymptomatic.

Since left-ventricular ejection fraction was normally distributed in the population without cardiovascular disease, the first question our study raises is “What is normal left-ventricular function?”. Our decision to choose

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