PMC9808478_01
Findings. (A) Electrocardiography. (B) Chest X-ray. (C-E) Echocardiography of systole (C), diastole (D), and color Doppler echo (E). Arrow indicates a trivial left-right shunt flow via the patent foramen ovale. (F-H) Coronary angiography. No significant coronary stenoses were observed. (I) Four-chamber image during Impella insertion with P7 and ECMO flow of 3.0 L/min clearly shows right-to-left shunt flow through the patent foramen ovale (PFO, arrows). (J) Hematoxylin and eosin staining of the myocardial sample (original magnification x400). Mixed inflammatory infiltrates comprising histiocyte giant cells and lymphocytes were observed. (K) Four-chamber image after weaning from Impella showing left-to-right shunt flow through the PFO. (L) Autopsy finding of PFO.
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Electrocardiography showed sinus tachycardia with a heart rate of 100 beats per minute, with first-degree atrioventricular block (PR 0.21 s) and wide QRS (QRS 0.147 s), indicating conduction disturbance (Fig. 1A). Chest X-ray showed marked pulmonary congestion and cardiac enlargement (Fig. 1B). Echocardiography showed reduced left ventricular ejection fraction (LVEF; 37.5 %) with diffuse hypokinetic left ventricular wall motion, and left-right shunt via PFO (Fig. 1C-E). Coronary angiography showed no significant stenosis (Fig. 1F-H), and we performed myocardial biopsy (right ventricle). Although transthoracic echocardiography was not clear due to Impella flow, transesophageal echocardiography clearly showed R-L shunt flow through PFO, which was considered to cause hypoxemia (Fig. 1I). On day 5, myocardial biopsy revealed giant cell myocarditis (Fig. 1J). Transesophageal echocardiography after Impella also showed a R-L shunt through the PFO, as observed on admission (Fig. 1K). He died on day 76, and an autopsy confirmed PFO, with a diameter of 10 mm (Fig. 1L).
Clinical time course.. Impella 5.0 support had stabilized hemodynamic state from days 2 to 3, but hypoxia progressed acutely without pulmonary congestion or infiltration on day 4. Although the fraction of inspiratory oxygen was elevated to 100 %, the partial pressure of arterial oxygen remained at 34.5 mmHg. We added V-A ECMO and weakened the Impella output level to P2, which led to recovery from hypoxemia.[V-A ECMO; veno-arterial extracorporeal membrane oxygenation].
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After admission, we started continuous intravenous administration of catecholamine (Fig. 2); however, the response was poor and lactate was also elevated. As desaturation was remarkable, we added V-A ECMO to maintain oxygenation, and then oxygenation was improved (Fig. 2).