Cardiovascular implantable electronic device lead safety: Harnessing real-world remote monitoring data for medical device evaluation

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Occurrence of implantable cardioverter-defibrillator therapy in clinical practice

The landmark trials MADIT II, SCD-HeFT, and COMPANION in 2002–2005 years have reported their positive results to sudden cardiac death reduction. Since that time the indications for the use of implantable cardioverter-defibrillators (ICDs) have substantially broadened. The occurrence of appropriate ICD therapy differs in the individual trials. We were retrospectively analyzing the occurrence of ventricular tachycardia/ventricular fibrillation (VT/VF) from ICD remote monitoring database (Biotronik Home Monitoring TM, www.biotronik-homemonitoring.com). No significant difference was found between subgroups divided by the implantation indication, the programmed ventricular stimulation, the aggressivity of programmed ventricular stimulation protocol, left ventricular ejection fraction, ICD types, percentage of right ventricular pacing, diabetes mellitus, renal dysfunction and gender. VT/VF occurred statistically significantly more often in patients with non-sustained VT on the preimplant Holter monitoring report in patients with primary preventive indication for postinfarction coronary artery disease but not in primary preventive indication for non-ischemic dilated cardiomyopathy. We observed higher VT/VF occurrence in patients with preimplant syncope or presyncope even higher than in patients after cardiopulmonary resuscitation. There was a visible trend for higher VT/VF occurrence in patients with positive programmed ventricular stimulation especially with less aggressive protocol and in patients with left ventricular ejection fraction of 30% and less. Authors found the preimplant nonsustained ventricular tachycardia (NSVT) on Holter monitoring as the only independent predictor of VT/VF occurrence.     

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.     

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。     

Development and testing of an algorithm to detect implantable cardioverter-defibrillator lead failure

BACKGROUND: Implantable cardioverter-defibrillator (ICD) lead failures often present as inappropriate shock therapy. An algorithm that can reliably discriminate between ventricular tachyarrhythmias and noise due to lead failure may prevent patient discomfort and anxiety and avoid device-induced proarrhythmia by preventing inappropriate ICD shocks. OBJECTIVES: The goal of this analysis was to test an ICD tachycardia detection algorithm that differentiates noise due to lead failure from ventricular tachyarrhythmias. METHODS: We tested an algorithm that uses a measure of the ventricular intracardiac electrogram baseline to discriminate the sinus rhythm isoelectric line from the right ventricular coil-can (i.e., far-field) electrogram during oversensing of noise caused by a lead failure. The baseline measure was defined as the product of the sum (mV) and standard deviation (mV) of the voltage samples for a 188-ms window centered on each sensed electrogram. If the minimum baseline measure of the last 12 beats was <0.35 mV-mV, then the detected rhythm was considered noise due to a lead failure. The first ICD-detected episode of lead failure and inappropriate detection from 24 ICD patients with a pace/sense lead failure and all ventricular arrhythmias from 56 ICD patients without a lead failure were selected. The stored data were analyzed to determine the sensitivity and specificity of the algorithm to detect lead failures. RESULTS: The minimum baseline measure for the 24 lead failure episodes (0.28 +/- 0.34 mV-mV) was smaller than the 135 ventricular tachycardia (40.8 +/- 43.0 mV-mV, P <.0001) and 55 ventricular fibrillation episodes (19.1 +/- 22.8 mV-mV, P <.05). A minimum baseline <0.35 mV-mV threshold had a sensitivity of 83% (20/24) with a 100% (190/190) specificity. CONCLUSION: A baseline measure of the far-field electrogram had a high sensitivity and specificity to detect lead failure noise compared with ventricular tachycardia or fibrillation.     

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.     

Performance of an implantable cardioverter-defibrillator lead family

Background

Lead failure is the major limitation in implantable cardioverter-defibrillator (ICD) therapy. Long-term follow-up data for Biotronik Linox ICD leads are limited. Therefore, we analyzed the performance of all these leads implanted at our institution.

Materials and Methods

All Linox and Linox Smart ICD leads implanted between 2006 and 2015 were identified. Lead failure was defined as electrical dysfunction (oversensing, abnormal impedance, exit block). Lead survival was described, according to Kaplan–Meier. Associations between lead failure and specific variables were examined. p < .05 was considered significant.

Results

We included 417 ICD leads. The median follow-up time for Linox (n = 205) was 81 months and for Linox Smart (n = 212) 75 months. During that follow-up time, 30 Linox (14.6%) and 16 Linox Smart leads (7.6%) showed a malfunction. The 5-year lead survival probability was 97.4% for Linox and 95.2% for Linox Smart (log-rank test, p = .19). The 6- and 8-year lead survival probability for Linox was 93.6% and 84.6%, and for Linox Smart 93% and 91.9%. The only factor significantly associated with lead failure was younger patient age at implantation (hazard ratio/year: 0.97, 95% CI: 0.94–0.99, p = .002).

Conclusion

This relatively large study with a long follow-up period highlights a relevant failure rate of Biotronik Linox leads. The performance of Linox versus Linox Smart ICD leads was comparable. Although we show an acceptable 5-year lead survival probability, we observed a marked drop after just 1 more year of follow-up. In an era of improving heart failure survival probability, a prolonged follow-up of ICD leads is increasingly clinically relevant.     

Interpreting device diagnostics for lead failure

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9例11次埋藏式心脏转复除颤器电风暴的临床观察

目的总结埋藏式心脏转复除颤器(ICD)电风暴治疗的体会。方法与结果9例置入ICD后发生电风暴11次。均去除诱因,心电监测下静脉推注美托洛尔和/或胺碘酮,其中,2例加行室性心动过速(VT)射频消融,另1例加行经皮冠状动脉介入治疗。11次ICD电风暴均全部纠治。结论静脉推注美托洛尔和/或胺碘酮、适时VT射频消融和/或急诊冠状动脉血运重建等综合治疗能有效终止ICD电风暴。     

Early automatic remote detection of combined lead insulation defect and ICD damage

Lead and implantable cardioverter defibrillator (ICD) devicefailure is a severe problem in ICD therapy and may occur withoutpreceding signs of deterioration. Insulation lead failure andsubsequent ICD defect 7 months after ICD implantation for secondaryprevention of sudden cardiac death (SCD) in a 70-year-old malewas automatically detected with the Home Monitoring system.Immediate lead and device replacement was performed. This caseillustrates the benefit of permanent automatic remote monitoringof implanted active devices.     

Advances in remote monitoring of implantable pacemakers,cardioverter defibrillators and cardiac resynchronization therapy systems

Unlike the standard quarterly or semi-annual direct ambulatory device interrogations procedures, state-of-the-art implantable electronic cardiovascular devices (IECD) enable their wireless remote interrogation and monitoring, and automatically send reports and special alerts on a daily basis. This allows physicians to respond more proactively to changes in patient or device status, more appropriately triage patient care, and more efficiently perform the post-implant ambulatory follow-ups. This review presents the-state-of the-art technology of remote IECD monitoring and summarizes the main clinical observations published through June 2008. Cardiovascular remote monitoring systems made by several manufacturers are currently in various phases of development, clinical investigation, and medical applications. Data collected in several completed and ongoing studies strongly suggest that this new technology will make important contributions, particularly with respect to the facilitation of IECD follow-ups, enhancement of patient safety and quality of life, and lowering of medical costs. Further technological advances and a more clear understanding and appreciation of the clinical and economic benefits of telecardiology, will likely increase sharply the use of remote IECD monitoring in upcoming years.     

Estimation performance of a reduced lead system during continuous 12-lead ECG ST-segment monitoring

Background

Reduced lead systems utilizing patient-specific transformation weights have been reported to achieve superior estimates than those utilizing population-based transformation weights. We report upon the effects of ischemic-type electrocardiographic changes on the estimation performance of a reduced lead system when utilizing patient-specific transformation weights and population-based transformation weights.

Method

A reduced lead system that used leads I, II, V2 and V5 to estimate leads V1, V3, V4, and V6 was investigated. Patient-specific transformation weights were developed on electrocardiograms containing no ischemic-type changes. Patient-specific and population-based transformations weights were assessed on 45 electrocardiograms with ischemic-type changes and 59 electrocardiograms without ischemic-type changes.

Results

For patient-specific transformation weights the estimation performance measured as median root mean squared error values (no ischemic-type changes vs. ischemic-type changes) was found to be (V1, 27.5 μV vs. 95.8 μV, P<.001; V3, 33.9 µV vs. 65.2 µV, P<.001; V4, 24.8 μV vs. 62.0 μV, P<.001; V6, 11.7 μV vs. 51.5 μV, P<.001). The median magnitude of ST-amplitude difference 60 ms after the J-point between patient-specific estimated leads and actual recorded leads (no ischemic-type changes vs. ischemic-type changes) was found to be (V1, 18.9 μV vs. 61.4 μV, P<.001; V3, 14.3 μV vs. 61.1 μV, P<.001; V4, 9.7 μV vs. 61.3 μV, P<.001; V6, 5.9 μV vs. 46.0 μV, P<.001).

Conclusion

The estimation performance of patient-specific transformations weights can deteriorate when ischemic-type changes develop. Performance assessment of patient-specific transformation weights should be performed using electrocardiographic data that represent the monitoring situation for which the reduced lead system is targeted.