Masquerade of a Silent Killer

Abstract

Congenital long QT syndrome (LQTS), referred to as a ticking time-bomb is a cause of sudden death in young infants, children and adults. Its prevalence is estimated to be 1 in 2500 to 1 in 10,000 individuals internationally, with no racial predilection. It should be viewed as an unrecognized rather than a rare condition. This is a descriptive report of eight children diagnosed to have congenital LQTS from 2000 to 2007, in Sarawak General Hospital, Kuching, Sarawak, Malaysia, the main tertiary referral hospital for Sarawak. The eight index patients were not related to each other. Three were girls and five were boys. Four were Bidayuh, one Chinese, one Chinese-Iban, one Sea-Dayak and one was Malay. The presenting age ranged from six weeks to 12 years. The presentation in three children was intermittent cyanosis of lips, recurrent febrile seizures, and chest pain with a warm sensation in the chest, respectively. Five children masqueraded as epilepsy and one was on two anticonvulsants, while two children had history of syncope, giddiness and palpitation. However, none of the children were on any of the offending drugs. None of the children had family history of deafness or sudden infant death syndrome. Case 5 had family history of drowning and unexplained accidents, and syndactyly, while Cases 1 and 4 had family history of unexplained death of infants. Cases 3 and 8 had a spontaneously closed ventricular septal defect and a small ostium secundum atrial septal defect, respectively. The physical examination was unremarkable in all of the patients. None had dysmorphic features, deafness, syndactyly, bradycardia or underlying medical conditions, and no electrolyte abnormalities were detected. The initial corrected QT interval (QT-c) in ECG ranged from 0.443-0.506 sec. and in the continuous 24-hour ECG, it ranged from 0.510 sec. to 0.593 sec. All patients had T wave abnormalities. Cases 1 to 4 and 7 had prolonged QT-c in asymptomatic family members. Case 5 was not available for follow up and hence could not be started on treatment. Seven patients were started on oral propranolol 0.5 mg/kg/day, which was slowly increased weekly, until the patients had relief of symptoms. All the 7 patients who were on propranolol exhibited good response to treatment. Unfortunately, genetic testing was not available, and the current case series is too small to construe any generalizations. Therefore, further studies in the community and hospital are recommended.

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