ICD implant in 6 year old with Jervell and Lange-Nielsen (JLN) syndrome

Joseph Theodore T1, Ponnagiri G.K.M. Dhilipan2, S. Ajay3

1Consultant interventional cardiologist and Electrophysiologist, Kauvery Heart City, Trichy.

2Senior registrar- CTVS department, Kauvery Heart City, Trichy.

3Resident, Kauvery Heart City, Trichy.

Introduction

Jervell and Lange-Nielsen syndrome (JLNS) is a rare autosomal recessive disorder characterized by congenital bilateral sensorineural hearing loss and prolonged QT interval, which can lead to life-threatening cardiac arrhythmias. This syndrome is a subtype of long QT syndrome (LQTS) and is associated with mutations in genes encoding for potassium channels. Early diagnosis and management are critical to prevent sudden cardiac death in affected individuals.

Case Presentation

A 6-year-old girl presented with a history of six episodes of syncope precipitated by emotions and exercise since the age of 3. She had congenital bilateral sensorineural hearing loss, for which a right cochlear implant was performed at the age of 3. The patient’s electrocardiogram (ECG) revealed a corrected QT interval (QTc) of 600 milliseconds and T wave alternans, raising suspicion for JLNS. Genetic testing was done which confirmed the diagnosis.

ECG (Pre ICD)

Despite medical management with beta-blockers, the patient continued to experience symptomatic episodes. Given the severity of her condition and the risk of sudden cardiac death, a subpectoral transvenous implantable cardioverter-defibrillator (ICD) was successfully implanted. The procedure was challenging due to her thin chest wall and young age, but it was performed without complications. ICD pacing has been done to decrease the QTc. If the patient presents again with symptoms, it has been planned to perform Left cardiac sympathetic denervation.

Discussion

JLNS is caused by mutations in the KCNQ1 or KCNE1 genes, which encode subunits of the potassium channels involved in cardiac repolarization. These mutations result in a dysfunctional potassium channel, leading to a prolonged repolarization phase of the cardiac cycle (QT interval prolongation). This prolonged QT interval predisposes patients to ventricular arrhythmias, including torsades de pointes, which can result in syncope, seizures, or sudden cardiac death.

The majority of JLNS cases are linked to mutations in the KCNQ1 gene, with a smaller proportion involving mutations in the KCNE1 gene. These mutations are inherited in an autosomal recessive manner, meaning that two copies of the defective gene (one from each parent) are necessary for the syndrome to manifest. Carriers of a single defective gene may exhibit a milder form of LQTS without the hearing loss.

The diagnosis of JLNS is based on a combination of clinical findings, ECG characteristics, and genetic testing. Key diagnostic criteria include:

  • Congenital bilateral sensorineural hearing loss.
  • Prolonged QT interval on ECG, typically greater than 500 milliseconds.
  • T wave alternans on ECG.
  • Family history of JLNS or sudden cardiac death.
  • Confirmation through genetic testing identifying mutations in KCNQ1 or KCNE1 genes.

Management of JLNS involves both pharmacological and non-pharmacological strategies aimed at reducing the risk of arrhythmias and sudden cardiac death. Beta-blockers are the first line of treatment and work by reducing sympathetic stimulation to the heart, thereby lowering the risk of arrhythmias. However, beta-blockers may not be completely effective in all patients. In patients who remain symptomatic despite medical therapy or those at high risk of sudden cardiac death, an ICD is recommended.

ICD is indicated in patients with h/o cardiac arrest, QTc>550ms, syncope before the age of 5, males>20 years with KCNQ1 pathogenic variant.

The device monitors heart rhythms and delivers shocks to terminate life-threatening arrhythmias, in this case ventricular tachycardia. Patients are advised to avoid triggers that can provoke arrhythmias, such as intense physical activity, emotional stress, and certain medications that prolong the QT interval. Genetic counseling is important for affected families to understand the inheritance pattern and the risks for other family members.

Conclusion

Jervell and Lange-Nielsen syndrome is a rare but serious condition that requires prompt diagnosis and management to prevent life-threatening cardiac events. This case underscores the importance of recognizing the characteristic signs and symptoms of JLNS, including congenital hearing loss and prolonged QT interval, and highlights the challenges in managing young patients with this syndrome. The successful implantation of an ICD in this patient, despite anatomical and age-related challenges, emphasizes the role of advanced therapeutic interventions in improving patient outcomes. Regular follow-up and comprehensive care are essential for managing this complex condition.

 

Dr Joseph T

Dr. T. Joseph
Consultant Interventional Cardiologist & Electrophysiologist

Dr. S. Ajay
DNB Cardiology Resident

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