A PREVIOUSLY healthy 6-year-old white boy was admitted to the hospital after a second episode of syncope. The first occurred several months before when while racing a sibling, he became limp and unresponsive for less than 5 minutes. On awakening, he was aware of his surroundings, but slept a great deal for the next several hours. He was fine until the day of admission when, while racing another sibling, he collapsed, became unresponsive for less than 5 minutes, and then became awake and alert. His medical history is remarkable for lack of routine immunizations, given his parents' medical convictions. There was no history of seizure disorder or cardiac arrhythmia. Family history was noncontributory.
On admission, he was a well-appearing boy. His height was 113 cm, 25th percentile; weight, 19.5 kg, 50th percentile. He had no dysmorphic features and resembled other family members. Remarkable findings included a 2/6 systolic ejection murmur maximal at the upper left sternal border that transmitted along the left sternal border as well as to the back on the left. S1 and S2 were normal; diastole, quiet; pulses, full and equal. Occasional premature beats were noted during auscultation. He was alert and responded to questions appropriately. Results of cranial nerve, motor, cerebellar, sensory, and deep tendon reflex tests were normal. A chest x-ray film showed a generous heart size with slight left ventricular prominence. Lung fields were clear. Electrocardiography showed sinus rhythm with frequent premature atrial contractions but no premature ventricular contractions. The QT interval was slightly prolonged at 0.45 seconds. The QRS axis was+130 with large Q waves over the right precordium and no Q waves over the left. Echocardiography (Figure 1) demonstrated a globular heart with left ventricular trabeculation. Shortening fraction was 28%. Hemodynamically insignificant mild pulmonary stenosis, pulmonary insufficiency, tricuspid regurgitation, and aortic insufficiency were also noted. Exercise study results were uneventful. Holter monitoring showed frequent premature atrial contractions but no evidence of supraventricular tachycardia. There were 2 premature ventricular contractions during the 24-hour monitoring. Results of an electroencephalogram were normal.
The risk of sudden death was explained to the parents. They chose to return in 1 month to pursue therapeutic options. Two weeks after discharge the patient experienced a syncopal event at home while running and playing. He collapsed and became unconscious. At the local emergency department he was apneic, cyanotic, and had weak pulses. He did not respond to full resuscitative efforts and was pronounced dead. A full autopsy was performed, which was remarkable for the 170-g (mean normal weight for age, 90 g)1 globoid heart with deep trabeculations in both ventricular walls (Figure 2).
Michel RS, Carpenter MA, Lovell MA. Pathological Case of the Month. Arch Pediatr Adolesc Med. 1998;152(7):709-710. doi:10.1001/archpedi.152.7.709