Diaphragmatic pacemaker failure in congenital central hypoventilation syndrome: a tale of two twiddlers

Two patients with congenital central hypoventilation syndrome (CCHS) experienced phrenic nerve pacer failure due to deliberate manipulation of the internal receiver implant ("twiddling"). The patients, aged 7 and 12 years, presented with repeated episodes of pacer failure associated with local pain over a period of 18 months. They had progressively coiled the pacing wires to the point of breakage, which only became apparent at surgery. The breaks were not recognized radiologically, although in retrospect progressive twisting of the wires was evident on serial chest radiographs. Both patients required replacement of the internal receivers under general anesthesia. We recommend that the chest radiograph that is undertaken to investigate the cause of pacer dysfunction include the internal receiver. A plain chest radiograph that demonstrates progressive coiling of the subcutaneous pacing wire should raise suspicion of pacer wire breakage regardless of the patient's age.