An 8-year-old previously healthy male was diagnosed with thrombotic thrombocytopenic purpura (TTP) and increased serum cardiac troponin I. Telemetry recorded non-sustained ventricular tachycardia, without ST-segment changes or other abnormalities on serial electrocardiogram. This case illustrates that cardiac monitoring by telemetry should be considered in high-risk TTP with elevated cardiac troponin.