Subcutaneous Implantable Cardioverter Defibrillator (S-ICD) Tanner Barnes BME 281

The Problem: 300,000 people die each year in the United States due to sudden cardiac arrest (SCA) 80-90% due to ventricular tachyarrhythmias People who have severe coronary heart disease are at a heightened risk for (SCA) Research shows that an implantable cardioverter-defibrillator (ICD) can reduce the chance of dying from (SCA)

A Solution: Transvenous implantable cardioverter-defibrillator (T-ICD) First human implant in 1980 Gained FDA approval in 1985 First were “shock only” Now able to provide pacing and have advanced rhythm discrimination

Problems with T-ICD: Infections in the venous system 2,201 patients required lead removals between 2000-2011 Complex and highly invasive operation T-ICD’s often unsuccessful in children Requires x-ray imaging to ensure the lead is placed correctly

A New Alternative: Cameron Health, recently purchased by Boston Scientific, pioneered the subcutaneous implantable cardioverter-defibrillator (S-ICD) and it was put into commercial use outside the U.S. in 2009 The (S-ICD) was approved for observational study by FDA Awaiting FDA approval for commercial use

Design of S-ICD: The S-ICD System is comprised of the following four devices: SQ-RX Pulse Generator 80-J biphasic shock Charge time to 80-J ≤ 10 seconds 5.1 year longevity 30 seconds post-shock pacing Q-TRAK Subcutaneous Electrode Q-GUIDE Electrode Insertion Tool (EIT) Q-TECH Programmer

Implantation of S-ICD: All components implanted just below the skin Only requires 3 small incisions Can be an outpatient procedure

Advantages: Less invasive surgery Eliminates potential for infection and damage to venous system May be implanted using anatomical landmarks Potential for less inappropriate shocks in children

Disadvantages: Size Battery life Twice that of current T-ICD Battery life 5 years as opposed to upwards of 10 with T-ICD Does not provide anti-tachycardia pacing (ATP) or bradycardia pacing

S-ICD in Children: Study conducted in UK with two boys, aged 10 and 12 Early clinical trials suggest less inappropriate shocks than T-ICD Can be implanted in children >30 kg Possible for children <30 kg Adapts to growth better than T-ICD

Latest Observational Study: 330 patients in 33 different centers 99% complication free after 180 days 100% success rate in converting induced VT/VF to sinus rhythm Only 1 out of 119 spontaneous VT/VF episodes required external defibrillation Storm episode 37 out of 38 discrete spontaneous VT/VF episodes were corrected with one or more 80-J shocks

Continued: The one episode terminated spontaneously while device was charging for second shock Unintentional therapy occurred in 13.1% of patients over an 11-month follow-up Similar to inappropriate therapy with T-ICD The mean time to therapy for all inductions was 14.6 seconds

Conclusion: The S-ICD system represents a viable alternative to conventional T-ICD therapy in patients at risk of death from VT/VF Low rate of major complications thus far in European market and in clinical studies FDA decision on approval should be announced in the near future

References McLeod, Dr. Karen, and Dr. Andrew McLean. "Implantation of a Fully Subcutaneous ICD in Children." Authors. Journal compilation. 35. (2012): 20-23. Web. 19 Oct 2013. Hauser, Dr.Robert. "The Subcutaneous Implantable Cardioverter-Defibrillator." Journal of the American College of Cardiology. 61.1 (2013): 20-22. Web. 19 Oct 2013. "Safety and Efficacy of a Totally Subcutaneous Implantable-Cardioverter Defibrillator." Circulation. 128. (2013): 944-953. Web. 20 Oct. 2013. "Superior Vena Cava Defibrillator Coils Make Transvenous Lead Extraction More Challenging and Riskier." Journal of the American College of Cardiology. 61.9 (2013): 987-989. Web. 20 Oct. 2013. Boston Scientific. Boston Scientific. Web. 20 Oct 2013. <http://www.bostonscientific.com/cardiac-rhythm-resources/cameron-health/sicd-system.html>. "What Causes Sudden Cardiac Arrest?." National Heart, Lung, and Blood Institute. N.p., 1 1 2011. Web. 20 Oct 2013. <http://www.nhlbi.nih.gov/health/health-topics/topics/scda/causes.html>. "Subcutaneous Implantable Defibrillator (S-ICD) System Advisory Panel Package Summary of Safety and Effectiveness Data." . FDA. Web. 20 Oct 2013. <http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/MedicalDevices/MedicalDevicesAdvisoryCommittee/CirculatorySystemDevicesPanel/UCM301237.pdf>. <http://www.epdoc.net/professional/patientpages/Equipment-and-Device-Images.aspx> Boston Scientific. “Fundamentals of ICD Therapy”. <http://www.columbia.edu/itc/hs/medical/hickey/docs/Evolution%20of%20ICD%20Therapy%20010907.pdf>