A case of pioneering subcutaneous implantable cardioverter defibrillator intervention in Timothy syndrome

Abstract

This case report presents a notable instance of subcutaneous implantable cardioverter defibrillator (S-ICD) implantation in a 9-year-old patient diagnosed with Timothy syndrome (TS), which is a rare condition characterized by mutations in the CACNA1c gene. Conventional therapies often have limited efficacy in managing TS. This case is significant, as it represents the youngest age for S-ICD implantation recorded in mainland China. While the absence of ventricular arrhythmias during hospitalization and follow-up is encouraging, it is not sufficient to conclusively establish the safety and feasibility of this intervention in young TS patients. Further research is needed to evaluate the long-term outcomes and to consider S-ICD as a potential standard treatment option for TS. Additionally, there is a need for a more detailed exploration of the molecular mechanisms underlying gene therapy and personalized interventions.

Keywords: Case report; Long QT; Subcutaneous implantable cardioverter defibrillator (S-ICD); Timothy syndrome; Ventricular arrhythmias.

Fig. 1

Images after syndactyly separation and the toes before separation. Panel A displays the surgical scars formed after bilateral syndactyly separation, finger web reconstruction, and dermatoplasty. The arrows indicate clear separation of the fingers, healing traces in the surgical area, and the overall appearance after surgery. In Panel B, the arrows indicate the syndactyly deformity without the separation procedure

Fig. 2

12-lead electrocardiogram of the patient. The electrocardiogram shows a marked prolongation of the QT interval, measuring approximately 800 ms, with a QTc of 666 ms

Fig. 3

S-ICD implantation procedure images and X-ray comparison before and after the procedure. Plane A illustrates the procedure. With the patient under general anesthesia and guided by X-ray, an approximately 5 cm incision is made horizontally along the mid-axillary line at the fifth rib level. Using an electric scalpel, the subcutaneous tissue is dissected down to the deep fascia, separating the anterior serratus muscle and latissimus dorsi to create the ICD pocket. A transverse incision, approximately 2 cm in length, was made below the xiphoid process, and the subcutaneous tissue was dissected down to the deep fascia. A tunneling tool is used to create a tunnel between the xiphoid incision and the left chest wall incision. The subcutaneous ICD electrode was implanted along the tunnel and fixed with one needle in the muscle layer. Along the tunnel created below the xiphoid process, another tunnel is made along the left edge of the sternum, and the electrode is implanted along this tunnel. The pulse generator of the Boston Scientific S-ICD is connected to the electrode leads and implanted into the pocket created between the anterior serratus muscle and latissimus dorsi, securing the pacemaker with sutures. Planes B and C display postoperative X-rays. Plane D presents a comparison of X-rays before and after the procedure

Fig. 4

Image of the procedural incision at 1 month postsurgery