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JCCASE-1137; No. of Pages 4 Journal of Cardiology Cases xxx (2019) xxx–xxx
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Case Report
Defibrillation failure with short ICD charge time: Internal short circuit of a Durata lead Ayako Okada (MD, PhD)a, Wataru Shoin (MD)a, Morio Shoda (MD, PhD)a,b,*, Hiroaki Tabata (MD)a, Hideki Kobayashi (MD)a, Takahiro Okano (MD)a, Koji Yoshie (MD)a, Ken Kato (MD)a, Koichiro Kuwahara (MD, PhD)a a b
Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano, Japan Department of Cardiology, Tokyo Women’s Medical University, Tokyo, Japan
A R T I C L E I N F O
A B S T R A C T
Article history: Received 14 June 2019 Received in revised form 31 August 2019 Accepted 12 September 2019
A 17-year-old male with hypertrophic cardiomyopathy underwent placement of a dual-chamber implantable cardioverter defibrillator (ICD) in 2010. In October 2016, he suffered a cardiac arrest. His ICD was interrogated after visiting our hospital. The shock failed, and ventricular fibrillation (VF) terminated spontaneously to sinus rhythm. The Durata lead (SJM, Sylmar, CA, USA) was removed for investigation. The lead had an internal abrasion of a right ventricular conductor cable at the superior vena cava coil. These findings suggest that the ICD shocks that failed to terminate the VF were delivered with low energy due to an internal short circuit of the Durata lead. The very short charge time indicates insufficient energy delivery, which may cause failure of cardioversion and defibrillation.
© 2019 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
Keywords: Durata lead Dual lead Superior vena cava coil Internal short circuit Optim
Introduction An internal short circuit of an implantable cardioverter defibrillator (ICD) lead may cause ineffective defibrillation therapy, which has been reported with the Riata lead (SJM, Sylmar, CA, USA). However, Durata, which is the next-generation ICD lead by SJM, has been considered more reliable until now. Case report A 17-year-old male patient with a family history of sudden death and hypertrophic cardiomyopathy was resuscitated from spontaneous ventricular fibrillation (VF) in October 2010, and a single-chamber implantable cardioverter defibrillator (ICD) was implanted one month later.
* Corresponding author at: Department of Cardiovascular Medicine, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan. E-mail address: [email protected] (M. Shoda).
The ICD consisted of a Current DR 2211-36 and a dual-coil ICD lead Durata 7120 (both from Abbott, Lake Bluff, IL, USA). The patient refused remote monitoring and presented to our outpatient clinic monthly. A single VF episode occurred in October 2012 that was successfully treated by appropriate shock delivery. Regular follow-up showed that all parameters of the device were functioning normally (mode VVI 40 bpm, RV sense >12 mV, capture threshold 1.0 V 0.5 ms, bipolar pace/sense lead impedance 390 Ohms, and high voltage shock impedance 58 Ohms). In October 2016, he was found lying unconscious at his high school, and he regained consciousness several minutes later. He was transported to our hospital, where telemetry of his ICD showed that spontaneous ventricular tachycardia had been detected correctly, and that anti-tachycardia pacing had been delivered twice, resulting in degeneration to VF. The ICD detected the VF immediately and delivered six shocks, which did not restore sinus rhythm (Fig. 1). The VF then resolved spontaneously within one minute. Analysis of the data stored during the ICD therapy showed that the charge time of all shocks except the first was only 2 to
https://doi.org/10.1016/j.jccase.2019.10.002 1878-5409/© 2019 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Okada A, et al. Defibrillation failure with short ICD charge time: Internal short circuit of a Durata lead. J Cardiol Cases (2019), https://doi.org/10.1016/j.jccase.2019.10.002
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Fig. 1.
The 5th and the last (6th) shock. The charge time is 2 s, too short to deliver 36 J. Both shocks are unsuccessful for terminating ventricular fibrillation. 35J, 35 Joules; VF, ventricular fibrillation; s, seconds.
Fig. 2.
Findings of superior vena cava (SVC) coil inspection. The arrow shows internal ethylene tetrafluoroethylene (colored blue) insulation abrasion breaching the right ventricular cable lumen 16.7 cm from the distal tip with inside-out abrasion of the silicone elastomer insulation under the SVC shock coil (removed).
Please cite this article in press as: Okada A, et al. Defibrillation failure with short ICD charge time: Internal short circuit of a Durata lead. J Cardiol Cases (2019), https://doi.org/10.1016/j.jccase.2019.10.002
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0J
Fig. 3.
Change of charge times due to insufficient delivery of the shock energy. The short circuit at the superior vena cava coil provoked an excessive DC current, resulting in an abrupt shut-off and a very low energy delivery associated with a very short charge time after the 1st to 5th treatments. This is because the high-voltage capacitor retains its residual charge after the 1st to 5th treatments. J, Joules; s, seconds; Tx, therapy.
3 seconds, and that the shock voltage lead impedance measurement was <10 V during the shock discharges.
Discussion Inside-out abrasion with an internal short circuit in a Riata lead and a Durata lead Serious adverse events, including death, were linked to Riata leads [1,2]. Riata and Riata ST leads were susceptible to abrasion because of the internal motion of ethylene tetrafluoroethylene (ETFE)-coated cables against and through the silicone elastomer insulation that comprises their lumen walls. The concern is that a high-voltage (HV) short circuit might not be detected during a routine check-up unless defibrillation threshold testing (DFT) is performed [3,4]. Durata, which is the next-generation ICD lead, is now covered with the silicone–polyurethane co-polymer Optim to reduce abrasion failure. The Durata lead is less susceptible to “inside-out” insulation failure than the previous Riata and Riata ST leads. The Optim coating might prevent exteriorized cables, and it provides a 50-fold increase in abrasion resistance compared with silicone [5,6]. However, an Achilles heel of the Durata lead is the underside of the shock coil, which is not covered with Optim, although the most recent Optisure lead (Abbott) is completely covered with Optim. Causes an internal short circuit in a Durata lead An internal short circuit of an ICD lead can result in ineffective defibrillation, and this had been reported with the Riata lead. However, Durata, which is the next-generation lead, has been considered more reliable. The Durata lead of this case was extracted using an excimer laser sheath, and the entire ICD system was exchanged. The extracted Durata lead appeared normal externally, without obvious abrasion. The superior vena cava (SVC) shock coil was removed for further evaluation. An internal insulation abrasion had breached the right ventricle (RV) cable lumens 16.7–17.5 cm from the distal tip. The ETFE coating on one RV cable was abraded at this location (Fig. 2). Visual assessment of the Durata ICD lead showed an internal abrasion of an RV conductor cable at the level of the SVC coil although neither low shock impedance nor sensing noises were found. These findings showed that the ICD shocks that failed to terminate VF were delivered with low energy due to an internal short circuit of the Durata lead, similar to the Riata lead.
Mechanism of very short charge time with shock failures The 2nd to 6th charge times were significantly shorter than the first charge time in the present case (Fig. 1). Therefore, each of the estimated delivered shock energies was extremely low, because the internal short circuit induced excessive current during a short discharge time, resulting in abrupt shut-off of the treatment (Figs. 1 and 3). If the Dynamic Tx algorithm had been available, it might have detected HV failure and electrically disconnected the short in the HV circuit of the SVC, resulting in restoration of ICD function. The Dynamic Tx algorithm checks for compromised vector integrity and finds another viable configuration to ensure HV shock delivery [7]. From this case report, the ICD shocks that failed to terminate VF with very short charge times except for the first charge time may indicate a short in the HV circuit (Fig. 1). Since this phenomenon is critical, we should be aware of the mechanism and trouble-shooting methods. If a dual-coil Durata has been implanted, it would be better to use the Dynamic Tx algorithm to avoid this rare complication.
Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Consent for publication Consent for publication of this case was obtained from the patient.
Conflict of interest The authors declare that there is no conflict of interest. Acknowledgments The authors would like to thank Minako Aono and Mebae Kobayashi for their technical assistance. References [1] Hauser RG, Abdelhadi R, McGriff D, Retel LK. Deaths caused by the failure of Riata and Riata ST implantable cardioverter-defibrillator leads. Heart Rhythm 2012;9:1227–35.
Please cite this article in press as: Okada A, et al. Defibrillation failure with short ICD charge time: Internal short circuit of a Durata lead. J Cardiol Cases (2019), https://doi.org/10.1016/j.jccase.2019.10.002
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[5] Sato T, Soejima K, Yoshino H, Shoda M. Unusual fracture in a Durata lead with shock coil fragmentation and cable externalization. Heart Rhythm Case Rep 2017;3:328–31. [6] Anand DS, David SH, Jonathan JL. Sudden and fatal malfunction of a Durata Defibrillator lead due to external insulation failure. PACE 2016;39:101–4. [7] Edward JS, Mark EK, Madhukar G. Catastrophic failure of Durata ICD lead due to high-voltage short during shock delivery. Heart Rhythm 2014;11:1733–4.
Please cite this article in press as: Okada A, et al. Defibrillation failure with short ICD charge time: Internal short circuit of a Durata lead. J Cardiol Cases (2019), https://doi.org/10.1016/j.jccase.2019.10.002