This apical 4-chamber view is obtained from a patient with shortness of breath being managed with escalation of diuretic therapy, which eventually led to hypovolemic hyponatremia. What does it show? What is the heterogeneous area adjacent to the left atrium?

It is hiatal hernia with gastric content. Patient has a long-standing history of gastroesophageal reflux and was told that their ‘stomach moved up into the chest’. LA compression by the hernia may cause dyspnea by increasing the pulmonary venous pressure leading to interstitial edema. In extreme cases, hemodynamic instability can result from impaired left ventricular filling. In addition, some patients may present with arrhythmias such as atrial fibrillation and heart block due to the pressure effect of hernia. Below are the labeled image and relevant illustrations.

The hernia is also seen on the right lateral scan while we are evaluating for pleural effusion or pulmonary edema (image below). It may be confused with atelectatic lung commonly seen in cases of pleural effusion. However, the structure seen here is much larger compared to the size of effusion, looks heterogeneous with air-fluid contents and appears to be lined by peritoneum. Remember, air is white, and fluid is black on ultrasound. On the other hand, atelectatic lung would look more like a liver with white dots inside (static air bronchograms).

Chest X-ray and CT scan are shown for better anatomic orientation. However, these were not from the exact same day as POCUS. CT shows gastric and transverse colon contents in the hernia.

Hiatal hernia is usually well visualized on the parasternal long axis view but in our patient, we couldn’t find a suitable window because of chest wall abnormality. Here are two excellent images from the stated reference demonstrating achalasia in the parasternal views (long axis and short axis-aortic valve level) – observe posterior to the LA. Hiatal hernia would essentially look the same. After the patient was made to drink a carbonated beverage, repeat scan shows mobilization of the heterogeneous contents inside the dilated esophagus, increasing its hypoechoic (fluid) content. In addition, LA compression seems to have worsened due to dilation of the esophagus. This is a good trick to differentiate between gastrointestinal contents and a mediastinal tumor.