The value of the electrocardiogram and chest X-ray for confirming or refuting a suspected diagnosis of heart failure in the community

There is a common assumption that a normal ECG or a normal heart size on chest X-ray virtually rules out a diagnosis of heart failure. To assess the value of the electrocardiogram and chest X-ray in identifying patients with chronic heart failure in the community. This study was a secondary analysis of data prospectively collected at the time of patient's enrolment in the EPICA study, an epidemiological study of the prevalence of heart failure in Portugal. A total of 6300 subjects were clinically evaluated. Patients who presented with symptoms or signs of heart failure, and/or were receiving diuretics for chronic heart failure (CHF) had a chest X-ray, ECG, and echocardiogram. The diagnosis of heart failure was confirmed in 551 cases. Patients with right atrial enlargement, atrial flutter, atrial fibrillation, 2nd degree-Mobitz I atrioventricular block, 1st degree atrioventricular block, left bundle branch block, lung interstitial oedema, and bilateral pleural effusion were more likely to be diagnosed with heart failure. For the diagnosis of heart failure, in the Portuguese population aged over 25 years, an abnormal electrocardiogram had an estimated sensitivity of 81%, and negative predictive value of 75%; an abnormal chest X-ray had an estimated sensitivity of 57%, and negative predictive value of 83%. Twenty five percent of patients with CHF had a normal ECG or chest X-ray. Our results show that electrocardiographic and roentgenographic features are not sufficient to allow heart failure to be reliably predicted in the community and support the recommendation that all patients with suspected heart failure should undergo echocardiography.