A Case of Riata® Dual Coil Defibrillator Lead Failure in a Patient with Ventricular Fibrillation
A 50-year-old man with a history of acute myeloid leukemia and Wolff-Parkinson-White (WPW) syndrome was brought to the emergency room of a local hospital with chest discomfort and syncope in 2001. His initial electrocardiography showed atrial fibrillation with rapid ventricular response and pre-excited QRS complexes, which was converted to sinus rhythm with direct arrent (DC) cardioversion. He had taken amiodarone for two years but stopped the medication by himself.\nIn 2007, he experienced chest discomfort again and presented to the emergency room of another university hospital. He took a 12-lead electrocardiography, which showed atrial fibrillation with rapid ventricular response and pre-excited QRS complexes. Sinus rhythm resumed with DC cardioversion.\nHe was referred to our institute for catheter ablation of WPW syndrome. Contrary to expectations, ventricular fibrillation was reproducibly induced with programmed ventricular stimulation during an electrophysiologic study. Considering his episode of unexplained syncope, he underwent ICD implantation. A single dual coil ICD lead (St. Jude Medical, Inc., RIATA® 1570) was percutaneously introduced via the right subclavian vein because the left subclavian vein was not visible, then advanced and placed in RV apex. Intraoperative lead parameters including sensing amplitude, threshold, and lead impedance were all within appropriate limits. The ICD lead was connected to the ICD device (Atlas™+VR®, St. Jude Medical, Inc., St. Paul, MN, USA). They were placed in the right infraclavicular subcutaneous site. He had chest radiography after ICD implantation ().\nApproximately 3 years after the ICD implant, he received multiple shocks in the same day. He had never received a shock over 3 years of follow-up (). The ICD interrogation revealed recurrent shock due to a high frequency of noise that is sensed by the device as ventricular fibrillation (). There was no evidence of other ICD malfunction, with a ventricular sensitivity of 0.3 mV as well as ventricular lead and shock impedances of 315 Ohms and 60 Ohms, respectively. After ICD interrogation, ventricular sensitivity was raised up to 0.6 mV. Chest radiography was not done at that time.\nAfter 6 months of follow-up, routine chest radiography revealed a significant split in the insulation of the ICD lead allowing the inner wire to protrude (). He underwent a fluoroscopic evaluation for conductor external canalization. Before fluoroscopy, we considered removing the lead. But, we decided to leave a failed lead and insert a new ICD lead instead because of the high risk of complication during lead extraction. Under local anesthesia and fluoroscopic guidance, a previously inserted generator was removed and the proximal part of the old failed lead was cut and capped with encap®. A new single dual coil lead (DURATA® 7120Q/58, St. Jued Medical, Inc., St. Paul, MN, USA) with active fixation was inserted through the right subclavian vein and placed to the right ventricular mid-septum. After intraoperative measurements of pacing threshold, signal, and impedance, the lead was connected to a new single chamber generator (FORTIFY VR® CD1231-40Q, St. Jued Medical, Inc., St. Paul, MN, USA). The device and lead were placed appropriately in the preexisted ICD pocket site, which were verified via postoperative chest radiography (). He has been followed up regularly with no further episode of inappropriate shock via the outpatient department for 6 months.