Safety of transvenous cardiac defibrillator and magnetic titanium beads system for gastroesophageal reflux disease: a case report

Gastroesophageal reflux disease is increasingly treated with minimally invasive reflux management systems such as LINX^®, a flexible bracelet of magnetic titanium beads that is laparoscopically implanted to wrap around and support the gastroesophageal junction (Fig. 1) [1, 2]. Based on non-clinical testing, the LINX^® system is magnetic resonance imaging (MRI) conditional up to 1.5 T (0.7 T for previous model) and the FDA recommends caution for concurrent use with cardiac implantable electronic devices (CIEDs) given the theoretical risk of electromagnetic interference (EMI). To our knowledge, there are no prior clinical reports of patients with coexisting LINX^® and CIED, reporting safety of these systems.

Fig. 1.

Magnetic beads of the LINX^® bracelet around the gastroesophageal junction

We report a case of a 59-year-old male who previously had the LINX^® system implanted for refractory gastroesophageal reflux disease. Shortly after, he was diagnosed with apical hypertrophic cardiomyopathy with intracavitary obstruction (50 mmHg gradient with exercise), and New York Heart Association (NYHA) class I symptoms with genetic testing revealing a variant of unknown significance in CSRP3. Given non-sustained ventricular tachycardia (VT) on cardiac event monitoring, family history of sudden cardiac death (SCD), and late gadolinium enhancement on cardiac magnetic resonance imaging with a calculated 5-year SCD risk 4.1%, he was recommended an implantable cardiac defibrillator (ICD) for primary prevention. Patient underwent an uneventful transvenous dual chamber ICD implantation (Medtronic Cobalt generator with 4076 right atrial lead and 6935M62 right ventricular lead). Although not a routine practice at our institution, we elected to proceed with defibrillation threshold (DFT) testing given unclear clinical evidence regarding the LINX^® system in close proximity to the right ventricular (RV) lead and the generator (Fig. 2). Patient underwent routine remote device interrogations with normal lead parameters, minimal atrial, or ventricular pacing, and no atrial or ventricular tachyarrhythmias. In-person device interrogation was performed at 1-year follow-up, which again was unremarkable. Specifically, the patient received no inappropriate shocks, and no high frequency noise episodes were detected. RV lead (closest to the LINX^® system) parameters including sensing, impedance, and threshold were stable throughout the follow-up period.

Fig. 2.

A Right ventricular ICD lead EGM and impedance values (last 1 year). B Chest X-ray (posteroanterior and lateral) showing the magnetic beads (blue arrows) in relation to the RV defibrillator lead. C DFT testing at implant showed normal sensing and defibrillation with a single shock with 10 J margin

We present the first case report of a patient without interaction between his LINX^® system and his CIED at short- and long-term follow-ups. Decision-making in such patients should consider additional theoretical risks until additional data with more patients is available.