Implantable defibrillator lead extraction with optimized standard extraction techniques

Background Implantable cardioverter-defibrillator (ICD) leads might not be extracted especially in developing countries because of the high cost and lack of specialized tools. We aimed to evaluate transvenous extraction of ICD leads using optimized standard techniques. Methods We prospectively analyzed clinical characteristics, optimized extraction techniques and the feasibility of extraction for 40 patients (33 males; mean age 47.9 ? 16.1 years) with 42 ICD leads. Results Complete procedural success rate was 95.2% (40/42), and the clinical success rate was 97.6% (41/42). One ICD lead required cardiothoracic surgery. Minor complications occurred in three cases (7.5%), and no major complications or death occurred. Locking stylets were used to extract most leads (34, 81.0%) and almost half of the leads (20, 47.6%) required mechanical dilatation to free fibrotic adhesions; these leads had been implanted for a longer period of time than the others (43.7 ± 18.2 vs. 18.4 ± 13.4 months, P < 0.05). Three-quarters of the leads (30, 71.4%) were extracted with locking stylets plus manual traction (12, 28.6%), or mechanical dilatation with counter-traction (18, 42.8%) by the superior vena cava approach and one-quarter of the leads (11, 26.2%) were removed by optimized snare techniques using the femoral vein approach. Median extraction time was 20 min (range 2–68 min) per lead. Linear regression analysis showed that the extraction time was significantly correlated with implant duration (r = 0.70, P < 0.001). Median follow-up was 14.5 months (range 1–58 months), no infection, or procedure-related death occurred in our series. Conclusions Our optimized procedure for transvenous extraction of ICD leads provides a practical and low-cost method for standard procedures.     

Inadvertent transarterial insertion of atrial and ventricular defibrillator leads

Inadvertent placement of pacemaker and implantable cardioverter-defibrillator (ICD) leads in the left ventricle (LV) is a rare but well-recognized complication of device implantation [1]. We report a case of inadvertent transarterial implantation of dual-chamber ICD leads; the ventricular lead positioned in the LV and the atrial lead positioned in the aortic root. The tip of the atrial lead migrated across the aortic wall and captured the epicardial surface of the left atrium. The diagnosis was made 5 years after the implantation procedure with no apparent adverse events directly related to left heart lead placement.     

Recurrence of ventricular tachycardia degeneration by low-energy implantable cardioverter-defibrillator shocks: a case report

Despite their proven efficacy at reducing mortality in selected patients, implantable cardioverter-defibrillators have some proarrhythmic effects. In this report, we present a case of a patient with recurrent ventricular tachycardia degeneration to ventricular fibrillation by appropriate low-energy implantable cardioverter-defibrillator shocks.     

Early failure of a small-diameter high-voltage implantable cardioverter-defibrillator lead

BACKGROUND: We have observed a higher than expected rate of Sprint Fidelis model 6949 lead failures in our practice. OBJECTIVE: The aim of this study was to assess the performance of small-diameter Sprint Fidelis high-voltage ICD leads. METHODS: The actuarial survival of Sprint Fidelis model 6949 leads implanted at our center was compared with that of the Sprint Quattro Secure model 6947. The United States Food and Drug Administration Manufacturers and User Facility Device Experience (MAUDE) database was searched for Sprint Fidelis models. RESULTS: The survival of 583 Sprint Fidelis 6949 leads implanted at our center between September 2004 and February 2007 was significantly less than 285 Sprint Quattro Secure model 6947 leads implanted by us between November 2001 and February 2007 (P = .005). Six patients presented with Sprint Fidelis lead failure 4-23 months after implant. Five of the six patients experienced multiple inappropriate shocks associated with pace-sense conductor and coil fractures; the sixth patient had a fixation mechanism failure. The MAUDE search rendered reports for 679 Sprint Fidelis leads. The most frequent complaints or observations were inappropriate shocks (33%), high impedance (33%), and fracture (35%). Of 125 leads analyzed by the manufacturer, 62 involved fracture of the pace-sense conductor or coil and the high-voltage (defibrillation) conductor. CONCLUSIONS: The Sprint Fidelis high-voltage lead appears to be prone to early failure. Its use should be limited until the failure mechanism is identified and corrected. Patients should be evaluated quarterly, and automatic lead test features should be enabled. While more data are needed, routine prophylactic replacement of intact, normally functioning Sprint Fidelis leads does not appear justified.     

植入型心律转复除颤器导线故障分析

目的总结分析我院植入型心律转复除颤器（ICD）起搏除颤导线故障病例特点。方法对2005年10月至2009年12月62例在我院新植入ICD导线患者进行随访分析,所有导线植入均以锁骨下静脉作为入路。随访中出现以下1项或多项异常考虑导线故障：（1）起搏阻抗永久性或间歇性〉2000n或〈250Q;（2）除颤高压阻抗〉200n;（3）心内电图证实除颤导线感知非生理性高频噪声导致误放电。结果中位数随访时间28（10～46）个月,4例患者（6．5％）诊断ICD导线故障,导线寿命18～38个月;临床均以ICD误放电至医院就诊,同时程控发现ICD导线起搏阻抗异常。其中1例患者放电前闻及ICD导线阻抗报警,4例患者均重新植入新的起搏感知导线。结论ICD导线故障是一个值得重视的临床问题。ICD导线阻抗报警功能可能有助于早期发现导线故障。如程控发现仅仅除颤导线起搏阻抗异常,植入新的起搏感知导线可以作为首选的故障处理方法。     

Optimizing implantable cardioverter-defibrillator treatment of rapid ventricular tachycardia: Antitachycardia pacing therapy during charging

BACKGROUND: Previous studies in implantable cardioverter-defibrillator (ICD) patients demonstrated the efficacy and safety of antitachycardia pacing (ATP) for rapid ventricular tachycardias (VT). To prevent shock delay in case of ATP failure, a new feature (ATP during charging) was developed to deliver ATP for rapid VT while charging for shock. OBJECTIVE: The purpose of this study was to determine the efficacy and safety of this new feature. METHODS: In a prospective, nonrandomized trial, patients with standard ICD indication received an EnTrust ICD. VT and ventricular fibrillation (VF) episodes were reviewed for appropriate detection, ATP success, rhythm acceleration, and related symptoms. RESULTS: In 421 implanted patients, 116 VF episodes occurred in 37 patients. Eighty-four (72%) episodes received ATP during or before charging. ATP prevented a shock in 58 (69%) of 84 episodes in 15 patients. ATP stopped significantly more monomorphic (77%) than polymorphic VTs (44%, P = .05). Five (6%) episodes accelerated after ATP but were terminated by the backup shock(s). No symptoms were related to ATP during charging. In four patients, 38 charges were saved by delivering ATP before charging. Of 98 induced VF episodes, 28% were successfully terminated by ATP versus 69% for spontaneous episodes (P <.01). CONCLUSION: Most VTs detected in the VF zone can be painlessly terminated by ATP delivered during charging, with a low risk of acceleration or symptoms. ATP before charging allows delivery of two ATP attempts before shock in the same time that would otherwise be required to deliver only one ATP plus a shock. It also offers potential battery energy savings.     

High voltage lead failure diagnosed at upgrade of single-chamber ICD to dual-chamber ICD with CRT.

We describe a case of defibrillation lead damage which was detected only during an upgrade procedure from single-chamber ICD to dual-chamber ICD with biventricular pacing. The damage was not detected during routine checks in the ICD clinic.     

Evaluation of morphology discrimination for ventricular tachycardia diagnosis in implantable cardioverter-defibrillators

BACKGROUND: To reduce inappropriate therapy from implantable cardioverter-defibrillators (ICDs), electrogram morphology discrimination has been developed to improve arrhythmia discrimination without compromising device safety. OBJECTIVES: The purpose of this study was to determine the accuracy of the morphology discrimination algorithm for detecting ventricular tachycardia (VT). METHODS: Stored electrograms of 795 tachyarrhythmias from 106 patients with a St. Jude Medical ICD (51 single-chamber and 55 dual-chamber) were analyzed by the investigators. The data were analyzed for morphology discrimination alone, sudden onset and stability, and morphology discrimination in combination with sudden onset and stability. Data were corrected for multiple episodes within a patient with the generalized estimating equation method. RESULTS: Using the nominal template match of 60%, morphology discrimination alone provided sensitivity and specificity of 78% and 95% for single-chamber ICDs and 63% and 92% for dual-chamber ICDs, respectively. Based on the receiver operator characteristic curve, the optimal-match percent threshold was 80% to 85% but at the expense of specificity. Morphology discrimination combined with sudden onset and stability increased sensitivity to 98% with specificity of 86% in single-chamber devices. In dual-chamber devices, the loss in sensitivity is compensated by rate branch analysis, yielding a sensitivity of 98%. CONCLUSION: Arrhythmia discrimination based on electrogram morphology has the potential to reject atrial tachyarrhythmias. However, there is a risk for underdetection of ventricular tachyarrhythmias if arrhythmia discrimination is primarily based on morphology. To guarantee patient safety in single-chamber devices, the morphology discrimination algorithm must be programmed in combination with established detection algorithms. In dual-chamber devices, loss of sensitivity is compensated by the V > A rate branch.