Figure 78-19 A–D, Serial electrocardiograms in a 5-year-old victim of fatal smoke inhalation. Note the progressive slowing of the heart rate from sinus tachycardia (A) to a terminal, very slow idioventricular rhythm (D). (From Walsh CK, Krongrad E: Terminal cardiac electrical activity in pediatric patients. Am J Cardiol 51:557, 1983.)