Congenital Type II Long Qt Syndrome

Introduction Long QT syndrome (LQTS) is a heart condition marked by delayed ventricular repolarization, typically shown as a prolonged QT interval on an ECG and around 80 % of cases are inherited [1,2]. This syndrome has three main subtypes: LQTS types 1, 2, and 3, each associated with mutations in different genes. A prolonged QT interval can result in various clinical manifestations, such as seizures, torsades de pointes, and life-threatening arrhythmias [3]. Case Presentation A 25-year-old woman, pregnant for the first time, arrived at the hospital due to irregular, painful uterine contractions. Her medical history included sick sinus syndrome, an implanted pacemaker, and a confirmed diagnosis of type II LQTS (KCNH2 mutation). The mother did not take beta-blockers during pregnancy. The baby was delivered at 40 weeks of gestation, via natural delivery with clear amniotic fluid. His weight, height, and head circumference were within normal limits. Apgar scores were 6/8. Antenatal screening revealed that the fetus carried the same KCNH2 gene mutation, which was associated with various arrhythmias. The newborn’s ECG was closely monitored in the hospital, with QTc values ranging from 0.417 to 0.457 ms (normal QTc < 450 ms). Mild bradycardia was observed, with a heart rate of 75 bpm. On the third day, based on the anamnesis and ECG findings, the newborn was diagnosed with type II LQTS. Treatment with Propranolol (2 mg/kg/day, divided into three doses) was initiated right away. The newborn was assigned an ORPHA code and was advised to follow up with a pediatric cardiologist in 3 months. Discussion Type II LQTS is caused by KCNH2 gene mutation, leading to potassium channel dysfunction and prolonged QT intervals. It increases arrhythmia risk, especially triggered by stress or noise. The diagnosis of congenital LQTS relies on the ECG as well as patient and family history taking. ECG testing is not always definite, up to 25 % of patients with an LQTS genotype could have a normal QT interval [3,4]. Conclusions The case illustrates the prenatal diagnosis and management of type II long QT syndrome in a newborn, following the detection of the same KCNH2 gene mutation in both the mother and the fetus. Early diagnosis and timely treatment with Propranolol are crucial in managing the condition and preventing potentially life-threatening arrhythmias.