Malignant Hyperthermia-Like Manifestations in a Two-Month-Old Child With Holt-Oram Syndrome Undergoing Cardiac Surgery

Abstract

HOLT-ORAM SYNDROME (HOS) is a rare congenital disorder associated with limb abnormalities, structural cardiac defects, and cardiac arrhythmias due to various abnormalities in TBX5, a member of the T-box gene family. Children with this disorder frequently present for orthopedic and congenital cardiac surgery. HOS may manifest with minor structural cardiac defects such as atrial septal defects or ventricular septal defects, though more complex defects such as hypoplastic left heart or truncus arteriosus have been reported. In addition, abnormal TBX5 gene products are implicated in the abnormal development of the cardiac conduction system, resulting in various cardiac arrhythmias. The genetic basis of the cardiac abnormalities associated with HOS is incompletely understood at present though abnormalities in ion conduction, particularly potassium conduction, may lead to atrial tachyarrhythmia. The authors present the case of an infant with HOS who underwent congenital cardiac surgery, developed intraoperative findings suspicious for malignant hyperthermia (MH), and responded favorably to standard MH treatment.