Case Presentation: A 78-year-old woman with amyotrophic lateral sclerosis presented with abdominal fullness. She had undergone tracheal tube intubation, mechanical ventilation and percutaneous gastrostomy 4 years previously because of difficulty in respiration and ingestion. Upon physical examination, her abdomen was distended with board-like rigidity and her legs were cyanotic. Her blood pressure was 96/71 mm Hg; heart rate, 98 beats/ min; and temperature, 34.1°C. Electrocardiography revealed ST-segment elevation in leads II, III, aVF and V1-3. On bedside echocardiography, wall asynergy was not apparent, but whirling air bubbles were observed in the cardiac chambers.Computed tomography revealed gastric and intestinal pneumatosis with portomesenteric venous gas, consistent with acute bowel necrosis. Gas formation was also observed in the aorta and pulmonary artery. We diagnosed her as having vascular air embolism due to bowel necrosis. Considering the risks and poor prognosis, the patient’s family elected against surgery and opted for supportive management. The patient died a few hours after her initial presentation.

Discussion: In bowel necrosis, gas formation often occurs in the bowel wall because of an increase in pressure caused by bowel distension or an overgrowth of gas-forming bacteria. The cases of air bubbles in the heart: Intracardiac air have been reported as a condition wherein air originating from bowel necrosis or interventional procedures, such as central venous catheter manipulation, reaches the cardiac chambers. Usually the lung works as a filter for air bubbles, but in cases of large volumes of gas exceeding the filtering capacity or the existence of patent foramen ovale, air may migrate into the systemic circulation and cause paradoxical coronary or cerebral air embolism.
ST elevation on electrocardiography (ECG) is manifested in a number of conditions besides myocardial infarction, including non-cardiac diseases such as subarachnoid hemorrhage, pulmonary emboli, and bowel obstruction. Compression of the coronary artery from the intra-abdominal pressure due to bowel distension is considered to be the cause of ECG changes, but the etiology remains unknown. In this case, we did not perform coronary angiography because of the patient’s poor condition, but we assumed that the coronary air embolism by the retrograde air from bowel necrosis was another possible explanation for the ST-segment elevation.

Conclusions: Bowel necrosis is a life-threatening acute abdominal disease that requires prompt diagnosis. Hepatic portal venous gas is known to be ominous sign for bowel ischemia. Air bubbles in the heart upon echocardiography are a rare finding, but also a fast and non-invasive diagnostic sign indicative of bowel necrosis.