Coronavirus disease 2019-related acute myocarditis in a 15-year-old boy.

Coronavirus disease (COVID‐19) is generally milder in younger adults than in older adults. Here we present a case of COVID‐19‐related acute myocarditis in a 15‐year‐old boy.

The patient developed fever, fatigue, and abdominal pain, and tested positive for severe acute respiratory syndrome coronavirus 2 on a polymerase chain reaction test the next day. He had no pre‐existing respiratory or cardiovascular disease. Two days after the onset, chest computed tomography revealed mild consolidation of the lungs and cardiomegaly, but no pleural effusion. He was admitted to the hospital because of a high C‐reactive protein (CRP) level and progressive hypoxemia. His blood gas analysis on supplemental oxygen showed the following: pH, 7.270; partial pressure of oxygen (pO2), 118 mmHg; partial pressure of carbon dioxide (pCO2), 44.7 mmHg; base excess, −5.8 mEq/L; and lactate, 6.4 mmol/L. His white blood cell count was 14 500 cells/µL. Blood chemistry showed creatine kinase (CK), 359 U/L; CK‐MB, 17 U/L; lactic acid dehydrogenase, 895 U/L; CRP, 15.23 mg/dL; troponin‐T, 3,930 ng/mL, and brain natriuretic peptide, 1,856 pg/mL. After tracheal intubation, he was transferred to our center with percutaneous pacing for severe bradycardia due to a complete atrioventricular (AV) block.

On admission, his vital signs were: heart rate (HR), 50 bpm (without pacing); blood pressure, 94/51 mmHg; and SpO2 (arterial oxygen saturation of pulse oxymetry), 98% (FIO2 [inspired oxygen fraction], 0.5). Chest radiography showed cardiomegaly (cardiothoracic ratio: 67%) without lung consolidation (Fig. 1a). An electrocardiogram (ECG) showed a complete AV block with a marginally widened QRS complex and prolonged QT interval (Fig. 1b). Echocardiography revealed diffuse hypokinesis – left ventricular ejection fraction (LVEF), 25% – and some pericardial effusion. He was diagnosed with COVID‐19‐related acute myocarditis.

Fig. 1

Chest radiography and electrocardiogram (ECG) findings on admission to our center. (a) Chest radiography reveals cardiomegaly without notable lung consolidation. (b) Complete atrioventricular (AV) block with marginal widening of the QRS complex and prolonged QT interval is seen on the ECG. There is no ST elevation or depression.

On admission, veno‐arterial extracorporeal membrane oxygenation (VA‐ECMO) was initiated with cannulas in the right common femoral vein for drainage and right common femoral artery for infusion, in addition to dexamethasone, remdesivir, and dobutamine. After ECMO initiation, the patient’s systolic blood pressure increased to 120 mmHg; however, the AV block persisted (HR: 40 bpm). To discontinue ECMO, we had to maintain his cardiac output by increasing his HR. We treated his bradycardia with isoproterenol instead of a temporary transvenous cardiac pacemaker because it was difficult to place a pacing lead in the fluoroscopy room with sufficient infection control. He experienced non‐sustained ventricular tachycardia, which resolved following administration of amiodarone.

His HR immediately increased to 65 bpm after isoproterenol administration. The ECMO was discontinued 2 days after admission, without complications.

We discontinued isoproterenol 4 days after admission, although an ECG showed a complete AV block, because his peripheral circulation had improved, and his LVEF was 35%. However, his HR decreased from 60 to 38–40 bpm, and his cardiomegaly worsened; isoproterenol was therefore reinitiated. We were unable to extubate him due to his level of sedation, muscular weakness, and ventilator‐associated pneumonia. We successfully performed extubation 4 days later, after administering ampicillin and respiratory rehabilitation, and discontinued sedative use. His LVEF improved to 45%, although his HR remained at 40–50 bpm without isoproterenol. He was transferred to another hospital for rehabilitation.

Recent studies have revealed several cardiovascular complications in adults with COVID‐19, including acute myocardial infarction, cardiac failure, pulmonary thromboembolism, and arrhythmia. Our patient's clinical course was typical for acute viral myocarditis. This case has two noteworthy features. First, other treatment options for cardiogenic shock could have been selected on admission, including a temporary transvenous cardiac pacemaker with inotropic agents. We selected VA‐ECMO because of the rapid worsening of the patient's cardiac function. Second, the patient's CK level was low, relative to the severity of cardiac involvement, and the AV block persisted despite a relatively quick improvement in left ventricular contraction. This may have been due to the conduction system being disproportionately impaired, relative to the degree of myocardial damage. Conduction disturbances are common in viral myocarditis. This case indicates that AV conduction disturbances can occur in COVID‐19‐related acute myocarditis, in keeping with other recent reports. ,

This is the first case of a teenager with COVID‐19‐related acute myocarditis in Japan. Caution should be taken to prevent complications in patients with COVID‐19 and concurrent severe conduction disturbances, such as high‐degree AV block.

Disclosure

The authors declare no conflict of interest.

Author Contributions

M.N. wrote the manuscript. K.H. helped in drafting the manuscript. All authors read and approved the final manuscript.

Patient consent

The patient and his father have provided written consent for the publication of this case report.