PATHOLOGICAL FINDINGS FOLLOWING SUDDEN-DEATH IN AN INFANT WITH HYPERTROPHIC CARDIOMYOPATHY AND SUPRAVENTRICULAR TACHYCARDIA

The cardiac conduction system from infants suddenly dying with hypertr ophic cardiomyopathy has not been described. We studied by serial sect ion examination the conduction system from a 13-month old infant also known to have had supraventricular tachycardia. At autopsy, there was cardiomegaly with asymmetric septal hypertrophy. Microscopic examinati on revealed myofiber disarray around an abnormally formed central fibr ous body, numerous nodoventricular fibers to both sides of the ventric ular septum, and fibrosis of the left bundle branch. We postulate that supraventricular tachycardia utilized a concealed pathway or the malf ormed AV junction. Death may have resulted from deranged hemodynamics secondary to supraventricular tachycardia.