Introduction: Acute viral myocarditis is an important cause of sudden cardiac dysfunction in previously healthy children. It may present with nonspecific symptoms such as vomiting, irritability , or respiratory distress, and can rapidly progress to acute heart failure, malignant arrhythmias, and death. Among viral etiologies, Parvovirus B19 is a recognized cause ofmyocardial inflammation and dilated cardiomyopathy . Early recognition and aggressive supportive management are crucial, though outcomes remain unpredictable. Case presentation: A previously healthy 2-year-3-month-old girl presented with six episodes ofvomiting over one day . Her mother reported palpitations. On examination, she was tachycardic (pulse rate 168 bpm) with a gallop rhythm and mild hepatomegaly . Electrocardiogram showed sinus tachycardia. Two-dimensional echocardiography revealed moderate-tosevere left ventricular dilatation with severe systolic dysfunction; ejection fraction was 39%. She was admitted to the paediatric intensive care unit and commenced on high-flow nasal oxygen, intravenous milrinone infusion, intravenous furosemide infusion, oral spironolactone, intravenous immunoglobulin, and intravenous methylprednisolone with careful fluid management. Serology for Parvovirus B19 was positive, and a diagnosis of viral myocarditis was made. Despite intensive management, she developed non-sustained ventricular tachycardia on day five, followed by cardiac arrest requiring intubation and synchronized intermittent mandatoryventilation. The following day , she developed ventricular fibrillation leading to refractory cardiac arrest and succumbed to acute heart failure. Conclusion: This case highlights the fulminant course of viral myocarditis in young children and its potential for rapid deterioration despite aggressive therapy . Early suspicion in children presenting with unexplained tachycardia and gastrointestinal symptoms is essential to improve timely diagnosis and management.