Case Report: Self-limiting penetrating cardiothoracic injury from a barbed shark dart involving the right atrium.

Introduction: Penetrating thoracic trauma accounts for only 1%-13% of chest injury hospitalizations but is associated with high mortality due to involvement of the heart, great vessels, and lungs. Among these, foreign body injuries with retained objects are rare, and the role of specific structural features such as barbs in limiting injury severity has not been well described. Case presentation: A 54-year-old male sustained a penetrating injury to the right anterior chest from a barbed shark dart while fishing. On admission, he was relatively stable but with compensated hemodynamics. Echocardiography showed pericardial effusion with signs of early tamponade. Chest CT confirmed that the cylindrical foreign body had traversed the chest wall, the middle lobe of the right lung, and the pericardium, with the tip abutting the right atrial wall. Emergency median sternotomy revealed that the barbed shark dart had penetrated the right lung and pericardium and reached the right atrium. Notably, the backward-facing barbs at the posterior end of the dart prevented further forward migration, thereby averting perforation of the posterior right atrial wall and catastrophic bleeding. The foreign body was removed, the atrial puncture site was repaired, and a wedge resection of the injured lung was performed. The patient recovered uneventfully and remained asymptomatic at 1-year follow-up. Conclusion: This case highlights a unique "self-limiting" mechanism of penetrating cardiac injury, in which the barbed structure of the foreign body paradoxically reduced the extent of cardiac damage. Injury patterns in penetrating thoracic trauma depend heavily on the kinetic energy and structural characteristics of the object. For stable patients, a multidisciplinary approach involving imaging-guided surgical planning is critical.