[Clinical characteristics and treatment of congenital long QT syndrome in 58 children].

Abstract

Objective: To assess the clinical characteristics, pathogenic genes and therapeutic effects of congenital long QT syndrome (LQTS) in children. Methods: A retrospective analysis included 58 LQTS children (37 boys, 21 girls; age of diagnosis (8.0±4.1) years, range 0.1 to 16.0 years) at Division of Pediatric Cardiology, First Hospital of Tsinghua University from August 2013 to November 2017. Each patient was evaluated with a detailed medical history, 12-lead resting electrocardiogram, Doppler echocardiography, and molecular genetic analysis. Results: Forty-eight of the children (83%) had a delay to diagnosis (0.7 (0.1, 2.0)years) and initially received a misdiagnosis. QT prolongation of unknown origin was found in 10 cases (17%), complex arrhythmic conditions in 27 cases (47%), myocarditis in 3 cases (5%), syncope of unknown origin in 3 cases (5%), epilepsy in 2 cases (3%), myocardial infarction in 1 case (2%), cardiomyopathy in 1 case (2%), and vasovagal syncope in 1 case (2%). Nine children presented with the positive family history of LQTS and three children had congenital nervous deafness. Twenty-one (36%) children presented with recurrent syncope, and 14 cases of whom had symptoms during physical activity and/or emotional stress. The common arrhythmias were ventricular arrhythmia (26 cases), sinus node dysfunction (18 cases), atrioventricular block (AVB) (12 cases), and atrial arrhythmia (6 cases). LQTS-associated pathologic or possibly pathologic mutations were found in 41 children (71%). Thirty-three children (57%) were treated with propranolol (22 cases), permanent pacemaker (PM) combined with propranolol (5 cases), PM (4 cases), and implantable cardioverter defibrillator (ICD) combined with propranolol (2 cases). Eighteen children (55%) were asymptomatic, thirteen children (39%) reported infrequent syncope, and one case (2%) died. Conclusions: LQTS in children is potentially malignant and present as phenotypic diversity and complex arrhythmias. LQTS-related pathogenic or possibly pathogenic mutations are identified in most of the children. Beta-blockers therapy is effective in reducing the risk of malignant cardiac events. Some children with LQTS should receive PM or ICD therapy.