Case Summary. An 18-year old man presented with a three-week history of abdominal pain, weight loss and bloody diarrhoea. He was profoundly septic, with generalised abdominal tenderness. CT and flexible sigmoidosopy confirmed colitis of the colon with rectal sparing. Laparotomy was performed when conservative management failed to improve his condition. Subtotal colectomy, with end ileostomy and mucus fistula formation, was performed in light of active colitis. Despite successful operative intervention the patient acute left ventricular failure, raising the possibility of giant cell myocarditis, which fully resolved before a definitive diagnosis could be reached. Discussion. It is possible that the transient cardiac failure in this case may represent an overwhelming inflammatory response or myocarditis. Inflammatory bowel disease is rarely associated with giant cell myocarditis (GCM). GCM usually affects a young population and its prognosis is variable, ranging from complete recovery, remission with recurrence and fatality. The management of this group of patients is still relatively experimental. Conclusion. Fulminant colitis can be associated with a rapid deterioration in cardiac function. Causes include sepsis, systemic inflammatory response syndrome or myocarditis. GCM should be considered in patients with new onset of left ventricular failure that decline rapidly.