Case

A previously healthy 5-year-old Black, non-Hispanic male presented with 1 day of fatigue and vomiting. He had no other symptoms such as fever, cough, congestion, rash, or diarrhoea. In the emergency department, he was poorly perfused with a heart rate of 170 bpm and rhythm revealed monomorphic ventricular tachycardia (Fig 1a). He was hypotensive with a lactate of 8 mg/dL. Complete metabolic panel showed elevated blood urea nitrogen 37 mg/dL and creatinine 0.91 mg/dL. Electrolytes including magnesium, calcium, phosphorous, and potassium levels were normal. Complete blood count was unremarkable. High-sensitivity troponin I was elevated at 1658 ng/L (normal range 3–7 ng/L) and brain natriuretic peptide was 2298 pg/ml (normal range <101 pg/ml). Chest radiograph showed cardiomegaly and pulmonary oedema. COVID-19 PCR was positive and his serology was negative. The patient had no known exposure to COVID-19, but a family member was a healthcare provider. Initially, he was interactive and talking. Due to hypotension and cardiogenic shock, synchronised cardioversion (1 J/kg) was performed with sedation without conversion. This was repeated (2 J/kg), but he remained in ventricular tachycardia. He became more hypotensive and obtunded and was emergently transferred to the ICU. He was loaded with lidocaine (1 mg/kg) and started on a continuous infusion without improvement. Echocardiogram showed severely decreased biventricular function without chamber dilation (supplementary material – ECHO clip). Central venous and arterial catheters were placed showing profound metabolic acidosis with venous saturation of 22%. He was loaded with amiodarone (5 mg/kg) and his heart rate slowed to 100 bpm, but he remained in ventricular tachycardia. He was intubated and synchronised cardioversion was performed after the amiodarone load, but was unsuccessful; therefore, he was cannulated to VA-ECMO via the right neck.

Figure 1.

(a) Initial EKG (top) showed wide QRS morphology concerning for ventricular tachycardia. (b) Bottom EKG showed the patient recovered to sinus rhythm.

He was treated with intravenous immunoglobulin (2 g/kg) and methylprednisolone (30 mg/kg daily for 3 days). His family declined treatment with Remdesivir. Amiodarone and milrinone infusions were continued during ECMO. His infectious workup (respiratory viral PCR, viral serum PCR/serology for adenovirus, enterovirus, cytomegalovirus, Epstein–Barr virus, and parvovirus and blood and urine cultures) was negative. His inflammatory markers were not severely elevated as seen in MIS-C (Table 1), and his Interleukin-1β and Interleukin 6 were normal. High-sensitivity troponin I peaked at 5948 mg/L and BNP peaked at 3207 pg/ml.

Table 1.

Initial inflammatory laboratory values

He was taken for atrial septostomy due to left atrial hypertension (mean left atrial pressure 28 mmHg) on ECMO. Angiography revealed normal coronary anatomy without stenosis or aneurysm. Endomyocardial biopsy was deferred due to risk of perforation and cardiac magnetic resonance imaging was deferred due to inability to perform on ECMO support and the fact that it would not change acute management. On day 4 of admission, the QRS narrowed and patient converted to sinus rhythm (Fig 1b). Therefore, amiodarone was discontinued. His inflammatory markers decreased and systolic function improved. He was decannulated on admission day 5 and did not require any intervention for the small atrial communication. He was extubated on day 6 and was transitioned from milrinone to enalapril due to mildly reduced function on a repeat echocardiogram. He recovered to his baseline neurocognitive status and was discharged home with outpatient physical therapy.