Hydropneumopericardium is a very rare complication of long-standing paraesophageal hernia, occurring as a result of rupture of the intrathoracic gastric volvulus into the pericardium. A chronic paraesophageal hernia that is complicated by gastric volvulus can develop into such surgical emergencies as acute gastric obstruction, strangulation, perforation, and rupture into adjacent structures. Subsequent hydropneumopericardium constitutes an acute emergency that requires immediate surgical treatment and pericardial drainage. Herein, we discuss what we believe to be the 1st reported case of hydropneumopericardium that presented as an acute coronary syndrome in a patient who had a chronic paraesophageal hernia (as a result of rupture of the gastric volvulus into the pericardium). The 80-year-old patient did not survive the condition.