Recurrent Hiatal Hernia Resulting in Rightward Mediastinal Shift: Diagnostics in Cardiology and Clinical Pearls.

On radiographic imaging, the finding of a right-sided heart location can be due to multiple etiologies and may be congenital or acquired. We present the case of a 71-year-old male with a self-reported past medical history of hiatal hernia and previously diagnosed dextrocardia. The patient experienced cardiovascular intervention following an ST-elevation myocardial infarction. In the cardiac workup, a low-voltage normal electrocardiogram confirmed dextroposition of the heart due to significant herniation of gastric contents into the thoracic cavity. This gentleman had presumably been diagnosed with dextrocardia, a right-left reversal of heart anatomy and electrophysiology, based on imaging and incomplete workup. Dextroposition refers to a rightward shift of the mediastinum with no changes in orientation of cardiac anatomy, and therefore unchanged directional orientation of conduction. This is an important distinction from dextrocardia, a mirror-image reversal of the cardiac chambers and heart location in the chest wall, such as that due to congenital ciliary dysfunction. A sliding hernia is an uncommon cause of the rightward mediastinal shift, with few such cases documented in the literature, and cardiovascular manifestations of hiatal hernias are discussed. This case exemplifies the role of an electrocardiogram in distinguishing between dextrocardia and dextroposition for accurate diagnosis and management.