2 | Case report
A 51-year-old man was trapped in a closed sewage tank for about 20 minutes during his project on August 6. He was in coma when pulled out without electrocardiographic abnormality(Figure 1A). Endotracheal intubation, and pure oxygen inhalation were arranged immediately. The patient has no significant medical background or family history. After treatment, His consciousness became clear gradually. However, electrocardiogram showed extensive elevation of ST segment (Figure 1B)and myocardial enzyme index were increased dramatically on August 8th. What’s more, ventricular fibrillation occurred on August 9th. Luckily, sinus rhythm and consciousness was restored about one minute after cardiopulmonary resuscitation. No obvious abnormality was found in coronary computed tomographic angiography (CTA), but pluse indicator continuous cardiac output (PICCO) suggested low cardiac output with 1.9L/min/m2 of the cardiac index (CI).
Cardiotonic drugs like levosimendan were not effective, so intra-aortic ballon pump (IABP) was implemented then. The ST segment decreased to normal with left ventricular ejection fraction(EF) increased to 46% on August 13th and then the IABP was removed. However, he slipped back into a coma with ST segment elevated and EF decreased to 31% again afterwards. So veno-arterial extracorporeal membrane oxygenation (VA-ECMO) was implemented. Two days later, his ST segment elevated again (Figure 1C) with extremely bad heart function (Movie S1).Coronary angiography(CAG) found no stenosis but cardiomyocyte hypertrophy was showed in the pathology of myocardial biopsy(Figure 2A) and mitochondrial swelling, dissolution as well as vacuolization were observed under electron microscopy(Figure 2B). In order to support heart function powerfully, we put IABP to cooperate with VA-ECMO.
After about 2 weeks’ support of V-A ECMO and 3 of IABP, his heart function gradually returned to normal without any support(Figure 1D,Figure 3, Figure 4).