“Aquarium Sign” Observed in All Four Cardiac Chambers During Mechanical Ventilation in a Heart Failure Patient

A 66-year-old man with a previous myocardial infarction was rushed to hospital in acute respiratory distress. On admission, he was immediately intubated and mechanically ventilated for hypoxemia (peripheral blood oxygen saturation: 80%). Transthoracic echocardiography (TTE) showed a left ventricular (LV) ejection fraction of 38%, so heart failure treatment was initiated. On the 7th day of hospitalization, the patient began a pressure support/continuous positive airway pressure trial with a positive end-expiratory pressure (PEEP) of 5 cmH₂O. Follow-up TTE before weaning from the ventilator revealed scattered microbubbles (so-called “aquarium sign”¹) in all 4 cardiac chambers (Figure A,B; Supplementary Movies 1,2). An immediate imaging with abdominal contrast-enhanced computed tomography (CECT) scan revealed hepatic portal venous gas (HPVG). Gastric wall thickening and poor contrast enhancement were also observed (Figure C,D). Emergency upper gastrointestinal endoscopy revealed multiple gastric ulcers for which conservative management was initiated. On the following day, repeat echocardiography showed resolution of the microbubbles in all cardiac chambers.

Figure.

Echocardiography showing “aquarium sign” in all 4 cardiac chambers (A,B). Contrast-enhanced computed tomography showing hepatic portal venous gas (red arrowheads) and gas within the left gastric vein (yellow arrow) (C,D). LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

We hypothesize that the use of PEEP during mechanical ventilation may have exacerbated right-to-left shunting through a patent foramen ovale, thereby contributing to the appearance of microbubbles in all 4 cardiac chambers, though the presence of a potential internal shunt cannot be ruled out. When the aquarium sign is observed in a cardiac chamber, acute mesenteric ischemia, gastric ischemia, or air embolism, which are associated with HPVG, should be considered, and immediate abdominal CECT should be performed.

Disclosures

K.K. is a Circulation Journal’s Editorial Team member.

Supplementary Files

Supplementary Movie 1. Apical four-chamber view on TTE.

Supplementary Movie 2. Parasternal short-axis view on TTE.

Please find supplementary file(s);

https://doi.org/10.1253/circj.CJ-25-0125

Reference

• 1.   Singh UN, Kapoor A, Aggarwal A, Kumar S, Poddar U. Hepatic portal venous gas and “the aquarium sign” due to intussusception in kawasaki disease. Echocardiography 2012; 29: E201–E203.