The Subcutaneous Defibrillator S-ICD: Advantages & Disadvantages

Hussam Ali, Pierpaolo Lupo, Sara Foresti, Guido De Ambroggi, Gianluca Epicoco, Angelica Fondaliotis and Riccardo Cappato

Arrhythmia & Electrophysiology Unit II

Humanitas Gavazzeni Clinics Bergamo- Italy

Arrhythmia &Electrophysiology Research Center

Humanitas Clinical & Research Center Rozzano (Milan)- Italy

ICDs: hystorical background

•  The inventor of ICDs was Mieczyslaw (Michel) Mirowski, a Polish cardiologist formed between Israel and United States.

Randomized Clinical Trials and ICDs

-  ICDs have proven their efficacy and superiority to AADs for prevention of SCD in survivors of cardiac arrest and in selected pts at high risk.

-  However, clinical benefits of conventional ICD therapy have been partially offset by the morbidity mostly related to the transvenous leads, the weakest link or Achilles Tendon of the transvenous ICD system.

- Adequate experience/skills are required to perform venous access and to position the intracardiac leads. - Related complications: pneumothorax, hemothorax, cardiac perforation, pericarditis, venous occlusion/thrombosis, systemic infection/endocarditis, valvular dysfunction, lead dislocation/failure.

- Fluoroscopy is required.

- Children: - small venous capacity - more prone to lead failure in the long term. - growth! - Selected pts Venous anomaly/occlusion, no venous access to the heart Intracardiac shunts (thromboembolic risk) High infection risk: HIV, dialisis Pts, etc. - Transvenous leads extraction, when needed, is associated with considerable morbidity & mortality, and requires considerable skills/costs.

Problematic aspects with transvenous leads:

S"ICD&Therapy&

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&&&&&

&&&&"&By&simplifying&implant&techniques,&S"ICD&is&also&meant&to&expand&the&use&of&ICDs&in&clinical&prac/ce.&

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Aim of technology

Evolving ICD Technologies

Epicardial ICD

Transvenous ICD

1980 1989 2008

Subcutaneous ICD

Invasiveness

Most Least

a&

b&CAN&

PRIMARY&(b"Can)&

ALTERNATE&(a"b)&

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2.#SELECT#the#colored#profile.##The#largest###QRS#peak#must#be#within#a#Peak#Zone.#

UNACCEPTABLELEAD

ACCEPTABLELEAD

3.##VERIFY#at#least#one#lead#is#####acceptable#in#all#postures.

INCORRECTPROFILE

CORRECTPROFILEPeak Zones

144cm

RA

LA

LL

LEAD4II

LEAD4III

LEAD4I

1.#RECORD:#Supine+Standing####25#mm/s,#5E20#mm/mV

SIMULTANEOUS439LEAD4ECG

14 cm

C

•  Entirely subcutaneous technology •  Fluoroscopy is not required •  Canister C (left lateral thorax) connected

to a single lead tunneled subcutaneously to the left parasternal line

•  3 sensing electrodes (A, B and D), Coil C •  A pre-operative screening tool to ensure

adequate subcutaneous signals of pts

The S-ICD System:

A C

B D

1st generation S-ICD SQ-RX 1010

(Cameron Health)

2nd generation S-ICD EMBLEM

(Boston Scientific)

12.7&&&mm&59.5&&&cc&

130&&&gram&7.3&&&years&LATTITUDE&

15.7&&&mm&69.9&&&cc&

145&&&gram&5.1&&&years&

Not&avaliable&

Thickness&&↓&20%&Volume&Weight&

Longevity&↑&40%&Remote"Monitoring&

The$subcutaneous$lead A$tripolar$parasternal$electrode$$(polycarbonate5urethane$55D,$3$mm$diameter,$45$cm$length)$

*From: Ali H, Lupo P, Cappato R. The Entirely Subcutaneous Defibrillator: A New Generation and Future Expectations. Journal of Arrhythmia & Electrophysiology Review, August 2015;4(2):116-121.

14 cm GUIDE (Note: For screening, ECG electrodes should not extend beyond 14 cm arrows)

2.#SELECT#the#colored#profile.##The#largest###QRS#peak#must#be#within#a#Peak#Zone.#

UNACCEPTABLELEAD

ACCEPTABLELEAD

3.##VERIFY#at#least#one#lead#is#####acceptable#in#all#postures.

INCORRECTPROFILE

CORRECTPROFILEPeak Zones

144cm

RA

LA

LL

LEAD4II

LEAD4III

LEAD4I

1.#RECORD:#Supine+Standing####25#mm/s,#5E20#mm/mV

SIMULTANEOUS439LEAD4ECG

14 cm

A&Pre5Opera@ve$Screening$Tool$was&developed&to&ensure&that&pts&have&suitable&subcutaneous&sensing&signals&

Implantation Technique Cartoon by

Boston Scientific

PA and laterla CXR after S-ICD implantation:

Optimal position: AP view Sub-optimal position: lateral view

Sensing&the&subcutaneous&signal….&

•  Three& bipolar& sensing& vectors&provide& maximum& sensing&flexibility.&

•  The& ICD& automa/cally& selects&the&signals&from&the&best&vector&for&arrhythmia&detec/on&and&to&avoid& double& coun/ng& and& T"wave&oversensing&

A

B

CAN

PRIMARY (B-Can)

ALT

ER

NAT

E (A

-B)

S-ICD Rhythm Detection

•  All detection algorithms work together to identify S-ECG rhythm: heart rate, QRS width and dynamic template matching with learning from previous beats

S-ICD Technical Manual

50#Hz#Induction#Pulse50#Hz#Induction#Pulse

Standard'Polarity'Shock Reversed'Polarity'ShockStandard'Polarity'Shock Reversed'Polarity'Shock

S-ICD Test in The EP-Lab, induced VF

Programming$Simplicity$

Only few programmable parameters!

A programmable conditional shock zone

(170-240 bpm)

Spontaneous Events

Europe/New&Zealand&•  Enrolment:&&55&pts&12&Dec&2008&!&13&Feb&2009.&Follow"up&10&mo&&Detec/on&of&VF&•  137/137&episodes:&&Sensi/vity&100%&•  Time"to"therapy: &14&±&2&sec&Conversion&of&VF&@&65J&•  52/53&(>98%)&pts&met&the&&primary&conversion&endpoint&

CE Trial; 55 Patients

Bardy et al, NEJM 2010;363:36

Evaluation oF FactORs AffecTing the CLinical Outcome and Cost EffectiveneSS of the S-ICD

The EFFORTLESS S-ICD Registry Design

•  International, multicentre, standard of care Registry to collect short, mid and long-term operational and clinical outcome data on the S-ICD system

•  Retrospective and prospective patients implanted since CE mark

•  Aiming to recruit up to 1000 patients •  5 year data post implant •  Centers to be included from all current commercial countries

EFFORTLESS S-ICD Therapy

Infection rate

Inappropriate shocks

Successful term

ination of spontaneous VT/VF

Successful term

ination of induced VF

Follow-up (m

o)

Ischemic%

EF%

I ° Prevention %

�%

Mean A

ge .yrs

No.Patients

S-ICD Cohorts/ Clinical Trials

3.6 %9%100%98%10

±167%34%78%80%5655CE Trial Bardy et al/NEJM 2010

5.6 %13%95.2%100%1141%36%79%74%52314IDE Study (US FDA)

Weis et al/Circulation 2013

9.9 %15%100%100%1214% -50%-33111UK Cohort

Jarman et al/Europace 2013

5.9 %13%100%100%1838%41%60%75%50118Dutch Cohort

Nordkamp et al/JACC 2012

-5%100%97.5%7.622.5%47%42.5

%70%4240German I Cohort Aydin et al/CircArrhy 2012

1.4 %7.2%100%95.5%7.215.9

%46%59.4%72%4569

German II Cohort Case-Control Study

Kobe et al /H.Rhythm 2013

2.8%13%100%99.7%18.637%42%63%72%49472EFFORTLESS Registry

Lambiase et al/EHJ 2014

11.1 at 3

years

13.1 at 3

years98.2%98.6%21.37.840% 70%50882

Pooled data (EFFORTLESS+ IDE)

Burke et al/JACC 2015

S-ICD Therapy

The START Study: Subcutaneous vs Transvenous

Arrhythmia Recognition Testing

S"ICD&System&Performance:&Therapy&Delivery&(inappropriate&therapy)…&

•  Inappropriate&Therapy:&–  Low$annual$inappropriate$

shock$rate$

–  Reprogramming$has$been$very$successful$at$mi9ga9ng$further$events$

–  Of$the$inappropriate$therapy$delivered,$the$majority$occurred$within$the$first$six$months$from$implant$and$was$subsequently$managed$with$reprogramming$

54%

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0%

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Patient2population2(shaded2area)

%2of2all2shocks2for

inappropriate2sensing2(columns)

Months2since2implant

Timing2of2shocks2for2Inappropriate2Sensing(5.5%2of2pts2w/2shocks2 due2to2inappropriate2sensing)

-  Patient screening prior to the implant to insure adequate transcutaneous signals (pre-operating screening tool)

-  Device optimizing to select the best sensing vector (supine/o r t h o s t a t i c p o s i t i o n s ) -  Dual zone programming is preferred (ex: conditional shock z o n e 1 8 0 - 2 2 0 b p m , s h o c k z o n e > 2 2 0 b p m ) -  Exercise test maybe helpful to evaluate the occurrence of myopotential oversensing/functional BBB during excercise

How to minimize inappropriate shocks in S-ICD Pts?!

2.#SELECT#the#colored#profile.##The#largest###QRS#peak#must#be#within#a#Peak#Zone.#

UNACCEPTABLELEAD

ACCEPTABLELEAD

3.##VERIFY#at#least#one#lead#is#####acceptable#in#all#postures.

INCORRECTPROFILE

CORRECTPROFILEPeak Zones

144cm

RA

LA

LL

LEAD4II

LEAD4III

LEAD4I

1.#RECORD:#Supine+Standing####25#mm/s,#5E20#mm/mV

SIMULTANEOUS439LEAD4ECG

14 cm

200

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Worldwide S-ICD implants

S-ICD TV-ICD Advantages/Disadvantages -/+ ++ Data on long-term performance

- (only 30 sec post-shock) ++ Chronic Pacing: antibrady- CRT- ATP

+/- ++ Device size/volume

> 7 years > 10 years Device longevity

Lattitude ++ Remote monitoring

(2016?) already availiable MRI Conditional

+/- (in women +?), submascular! + Cosmetic aspect

-- -/+ Device cost $

++ +/- (recalls, lead failures, crush syndrom)

Lead performance

+ - Fluroscopy during implantation

- + Need for deep sedation/general anesthesia

- recommended +/- not routinely performed DFT is mandatory

simple, flexible sensing (3 vectors) Complex, numerous parameters programmable

Programming

+ - - Serious acute complications/infections

+ - - Extraction complexity

++ ++ Detection & Defibrillation efficacy

+/- (TWOS) +/- (AF + SVT) Inappropriate therapies

*From: Ali H, Lupo P, Cappato R. The Entirely Subcutaneous Defibrillator: A New Generation and Future Expectations. Journal of Arrhythmia & Electrophysiology Review, August 2015;4(2):116-121.

The&PRAETORIAN&Trial&A&Prospec/ve,&RAndomizEd&comparision&of&&subcuTaneOus&&&tRansvenous&ImplANtable&cardiovertor"defibrillator&therapy&

ESC Guidelines 2015

•  After more than a decade of continuous research/studies, the S-ICD has become a real life clinical practice for primary/secondary prevention of SCD unless pacing is required.

•  S-ICD avoids procedural difficulties/complications associated with TV- leads, and does not require routine fluoroscopy use.

•  The S-ICD is particulary beneficial in young patients, those with electrical syndromes, patients who had already experienced complications related to the TV-leads (serious infections, venous occlusion..)

•  Further technology innovations as Leadless Pacing, if integrated with the S-ICD might offer an attractive therapeutic approach in the future

•  Considering the simplicity of its implantation/removal, the S-ICD may fill the gap between the current indications for ICD therapy and the clinical practice. It might expand indications for ICD therapy in the future?!

CONCLUSIONS

Thank you for your attention