Echocardiography is not indicated for an enlarged cardiothoracic ratio

An increased cardiothoracic ratio (CTR) on chest X-rays is a not uncommon reason for requesting echocardiography. To assess how often the echocardiogram was abnormal in patients with an increased CTR, the results of 62 open-access echocardiograms requested with this indication were analysed. 

Means, standard deviations and 95% confidence intervals were calculated for the left ventricular diameters of the patient group investigated. Two-tailed t-tests were used to compare those with and without reported breathlessness, and those with additional radiology consistent with heart failure. Positive predictive values (PPVs) were calculated.

Only four echocardiograms were abnormal, giving a PPV for CTR of 6%. This increased only slightly to 15% with the inclusion of another radiological abnormality, and to 19% with a symptom or sign. We, therefore, conclude that an increased CTR alone is not a valid reason for requesting echocardiography.