Patients with fulminant myocarditis accompanied by severe hemodynamic deterioration, cardiogenic shock, or refractory arrhythmias often require venoarterial extracorporeal membrane oxygenation (VA-ECMO) treatment. When left ventricular (LV) dilation, elevated LV end-diastolic pressure, or severe pulmonary congestion occurs during VA-ECMO, LV venting may be necessary to protect the left ventricle. In this case series, we describe a percutaneous LV venting technique in three pediatric patients with fulminant myocarditis treated with VA-ECMO. Specifically, a pigtail catheter was retrogradely inserted into the LV and used as a venting device. Effective LV unloading was achieved in all patients, allowing successful weaning from ECMO. One patient developed limb ischemia requiring distal perfusion, but no additional catheter-related complications occurred. This approach offers a less invasive option for LV unloading in pediatric VA-ECMO, providing technical simplicity and reducing both the surgical burden and bleeding risk. To the best of our knowledge, this is the first case series to detail the use of a pigtail catheter for LV unloading in pediatric VA-ECMO.