A straight left heart border: a new radiological sign of a hemopericardium

Detection of a cardiac injury in a stable patient after a penetrating chest injury can be difficult. Ultrasound of the pericardial sac may be associated with a false negative result in the presence of a hemothorax. A filling in of the left heart border inferior to the pulmonary artery, called the straight left heart border (SLHB), is a radiological sign on chest X-ray that we have found to be associated with the finding of a hemopericardium at surgery. The aim of the present study was to determine if this was a reliable and reproducible sign.

This was a prospective study of patients with a penetrating chest injury admitted between 1 October 2001 and 28 February 2009, who had no indication for immediate surgery, and were taken to the operating room for creation of a subxiphoid pericardial window (SPW). The chest X-ray was reviewed by a single trauma surgeon prior to surgery.

A total of 162 patients with a possible occult cardiac injury underwent creation of a SPW. Fifty-five of the 162 patients (34 %) were noted to have a SLHB on chest X-ray and a hemopericardium confirmed at SPW. The sensitivity of the SLHB sign was 40 %; specificity, 84 %; and positive predictive value, 89 %. (p = 0.005, Odds ratio 3.48, lower 1.41, upper 8.62).

The straight left heart border is a newly described radiological sign that was highly significant in predicting the presence of a hemopericardium and should alert the clinician to a possible occult cardiac injury.