Subcutaneous Implantable Cardioverter Defibrillator (S-ICD)

Tanner BarnesBME 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: 1.SQ-RX Pulse Generator– 80-J biphasic shock– Charge time to 80-J ≤ 10 seconds– 5.1 year longevity– 30 seconds post-shock pacing

2.Q-TRAK Subcutaneous Electrode3.Q-GUIDE Electrode Insertion Tool (EIT)4.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– 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>