Thoracoscopic Left Cardiac Sympathetic Denervation in a Child with Refractory Long QT Syndrome.

Long QT syndrome is a cardiac disorder which presents with recurrent syncopal attacks and has risk of sudden cardiac death. A 5-year-old boy presented to us with this syndrome. The child was symptomatic despite medical management and was successfully managed with cardiac denervation. The current report highlights the efficacy and safety of the use of video-assisted thoracoscopic surgery for this procedure. Copyright:

INTRODUCTION

Long QT syndrome (LQTS) is a heterogeneous group of disorders characterized by paroxysmal attacks of syncope and propensity of sudden cardiac death. Various treatment modalities in children with LQTS include medications, implantable cardioverter defibrillator (ICD), and left cardiac sympathetic denervation (LCSD). LCSD is done in children having recurrent episodes of arrhythmia despite maximal doses of beta-blocker or children with arrhythmia bursts despite an ICD. Herein, we present a case of refractory LQTS in a 5-year-old boy. The child was successfully treated with LCSD by video-assisted thoracoscopic surgery (VATS) approach.

CASE REPORT

The index case is a 5-year-old boy with a family history of sudden cardiac death in two elder siblings at 5 years and 11 months of age, respectively. This child first presented to us at 10 months of age with multiple episodes of syncope. He was found to have a prolonged QT interval (0.579 s) on a 12-lead electrocardiogram and was started on beta-blockers (propranolol). One week later, he had another life-threatening episode of syncope with documented asystole on electrocardiogram. Thus, an epicardial pacemaker was implanted, and dosage of his beta-blocker medication was increased. The child was apparently asymptomatic for 4 years when until recently, he developed recurrent episodes of dizziness. In view of similar episodes of asystole, he underwent LCSD by VATS. A preoperative chest and upper abdominal X-ray [Figure 1] was done to look for the course of pacemaker wire to avoid interference within the surgical field.

Figure 1

Preoperative chest and upper abdominal X-ray ([a] – posteroanterior view; [b] – lateral view) shows the course of cardiac pacemaker wiring to avoid interference within the surgical field

Perioperative

Under general anesthesia, left lung isolation was achieved using a bronchial blocker placed under fiber-optic guidance. The child was positioned in a right lateral position (leaning anteriorly by 30°), and three small incisions were made along the midaxillary line at the level of left 2nd, 4th, and 6th intercostal spaces. Three 5-mm thoracoscopic ports were introduced through these incisions. After careful identification of the first rib and sympathetic chain, parietal pleura was incised over the sympathetic chain at the level of T5 ganglia and was extended proximally. Subsequently, sympathetic chain was dissected [Figure 2] and transected from the level of T2–T5. The entire dissection was performed using a Harmonic scalpel. Use of electrocautery was avoided due to electromagnetic interference and possible malfunctioning of the pacemaker. Stellate ganglion was preserved to avoid the occurrence of Horner's syndrome. A chest tube was placed in one of the port sites (6th intercostal space) before closure. The procedure was completed with minimal blood loss. A reduction in QTc interval was achieved within 24 h of surgery (reducing from 0.579 s preoperatively to 0.449 s postoperatively). However, heart rate and ventricular function remained unchanged. The child was discharged uneventfully on the 4th postoperative day. After 8 months of regular follow-up, there were no further episodes of syncope, due to which his beta-blocker dose is reduced to minimum.

Figure 2

(a) Intraoperative magnified view of the sympathetic chain. (b) Stellate, T2, and T3 sympathetic ganglia are marked

DISCUSSION

LQTS is a group of electrophysiological disorders of the heart characterized by a prolonged QT interval (>460 msonds) on a 12-lead electrocardiogram due to delayed ventricular repolarization. This creates a proarrhythmogenic state by episodic polymorphic ventricular tachycardia manifesting as recurrent syncopal attacks and sudden cardiac death.

Its prevalence is approximately 1 in 2500 live births. The syndrome has an autosomal dominant inheritance pattern with variable penetrance.[1] Genetic mutations in myocyte ion channels have been considered the cause in the majority of children. Three major genotypes, i.e., LQT1, LQT2, and LQT3 constitute >90% of the mutations seen in LQTS patients.[2]

Treatment options for children with LQTS include medical, surgical, and implantable devices. Medical therapy in the form of beta-blockers is considered as first-line treatment for these children. Its possible mechanism of action is by reduction of adrenergic-mediated triggers.[3] ICD is indicated in cardiac arrest survivors and children who continue to experience recurrent syncopal episodes while on beta-blocker therapy. While ICD is a boon to these subsets of patients, it has some risks and side-effects. It has been found that 25% of patients may receive inappropriate shocks (during nonfatal arrhythmias). This can lead to depression, anxiety, and a significant reduction in quality of life, particularly in children and adolescents. Pacing hazards and hardware malfunction are other limitations of ICD use.[4]

LCSD is another modality for the treatment of children with LQTS. LCSD is indicated in children experiencing recurrent syncopal episodes despite maximum dose of beta-blockers and participants having arrhythmia storms even in the presence of an ICD. The procedure was first described in 1971 when a unilateral cervicothoracic sympathetic ganglionectomy was performed in a 39-year-old woman with LQTS. Over time, this technique has evolved immensely. In the present era, the technique of high thoracic left sympathectomy involving removal of lower-half or lower-third of stellate ganglion along with sympathetic ganglia from T2 to T4 is preferred. It precludes the risk of Horner's syndrome as most of the sympathetic fibers to the ocular region traverse the upper portion of the stellate ganglion and thus are spared. A study by Schwartz et al. in 2004 established a significant reduction in aborted cardiac arrests and syncopal attacks in high-risk LQTS participants following LCSD.[5] Common side effects of the procedure may include dry left arm, face, and forehead with exaggerated sweating (Harlequin-type flushing) on the right side.

With the modern era of minimally invasive surgery, LCSD by VATS approach is gaining its popularity. It was first performed by Reardon et al. in a 6-year-old girl with LQTS in the year 2000. Since then, promising results using this approach in the treatment of refractory LQTS have been demonstrated by various studies across the globe. A recent study depicted the safety and efficacy of LCSD performed by VATS approach in children with life-threatening ventricular arrhythmias. Stellate ganglion was intentionally spared in 23 of 24 patients. Minor complications including small apical pneumothorax and Harlequin facial flushing (not Horner's) were seen in the postoperative period. No major complications were observed.[6]

CONCLUSION

Similar operative outcomes have been achieved in LCSD by VATS approach as compared to an open approach establishing its role as a preferred approach wherever feasible. Brief operative time and postoperative hospital stay, minimal blood loss, and a magnified view of the posterior mediastinal structures (including sympathetic chain) are major advantages with the thoracoscopic approach.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.