icd system high voltage component failure (presented to fda)

ICD Lead High-Voltage Component Failure

How to Identify ICD Leads and Systems That Will Not Deliver Shocks

Edward J. Schloss MD FACC FHRS

Presented to FDA

October 14, 2014

Disclosures

• Medtronic: Consultant, Speaker

• Boston Scientific: Consultant, Speaker

Components of ICD System

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

ICD Can

Low Voltage Function - Sensing

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

ICD Can

Low Voltage Function - Pacing

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

ICD Can

High Voltage Function

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

ICD Can

High Voltage Failure is Tough to Detect

• Impedance is only measured parameter– No sensing/noise alerts, no pacing threshold

• Testing amplitude is order of magnitude less than working stress on lead

• Failure may be asymptomatic and go undetectedfor years

• First presentation may be sudden cardiac arrest or death– High voltage failure is “quiet”– May go undiagnosed if no postmortem interrogation

How does HV Failure Present?

• Silent failure, picked up with remote notification



• Silent failure, picked up in office




• Silent failure, seen w/hospital shock testing

“annual DFT testing, once a common clinical practice is performed infrequently today”

JACC Aug 2008




• Silent failure, picked up w/hospital HV testing

• Clinical Shock with manifest failure

– Inappropriate




• Silent failure, picked up w/hospital HV testing

• Clinical Shock with manifest failure

– Inappropriate

– Appropriate

Lee Oukrup with portrait of son Joshua www.nbcnews.com

How Do We Detect HV Component Failure?

• What can fail?

– Pulse Generator


• What can fail?

– Pulse Generator

– Generator/Lead Interface – i.e. header


• What can fail?

– Pulse Generator

– Generator/Lead Interface – i.e. header

– Lead

• Weakest Link in the Chain

• Types of Failures

– Conductor

– Insulator

Shock Lead Impedance Testing

• Pulse delivered automatically every 21 hours– Older generation devices 15 mA for 60 μsec

– Newer generation devices 80 μA for 156 μsec (10 Ω higher)

• Red Alert in Latitude if >125 Ω or <20 Ω(programmable)

• Measures each TRIAD vector separately and combines to single value


• Pulse delivered once a week

– 4V for 20 msec, Coil to can

• Normal defined as <400 Ω

• Abnormal will show up as alert on interrogation

• With shock, normal is <200 Ω


• Pulse delivered daily (up to 4 attempts)– 400 mV for 90 msec

• Two vectors reported– HV Impedance = RV coil to SVC coil+Can

– SVC Impedance = RV coil to SVC coil

• Alarm for Impedance < 20Ω, > 200Ω (programmable)

• Triggers clinician and patient alert (not LIA)


• Atlas/Epic have no daily measurements

• Physician generated HVLI test (12v)

• Later Generations HV pulse delivered daily

– All vectors (RV and SVC to can)

• Alert impedances are programmable

Evidence Base for Shock Lead Integrity Testing

Canine ModelLooked intact and disrupted (high Ω) lead configurationsPacing pulses and shocks measured over wide range of impedances from normal to highClose correlation suggests low voltage measurements predict high impedance failure

Did not test for low impedance failure


Validation of newly developed HV testing technique29 pts with Guidant PRIZM ICDs at implantAll pts got 0.4 μ J pulse, 1.1 J, and 16-45 J shocksImpedances measured for all pulse strenthsLow energy pulses correlated with high energy shocks

Only new functional leads were tested


"Partial insulation defects may not be identified by low-energy pulses that deliver insufficient current to activate the shorted high-output protection feature."

Swerdlow/Friedman Pacing Clin Electrophysiol. 2006;29(1):70-96.

Response to Failed Shock

Conductor Failure – High impedance

– Cable fracture, Set screw issue

• Fidelis

– Current delivery attenuated to affected limb of circuit

• RV coil likely ineffective shock

• SVC coil likely effective shock unless high DFT

– Device will be unharmed and report out a high impedance alert

Response to Failed Shock Insulator Failure – Low impedance

– Abrasion: can/coil , coil/coil, Header short• Riata, PRIZM 2 DR

– HV Current pulse generator as a short• Older devices: current shunted from heart , electrical

overstress may damage PG

• Newer devices: current shunted, PG protected.

– If PG is still intact, low Ω alert issued.

– St. Jude Dynamic Tx• Reconfigures shock to remove SVC coil or can from

circuit if breach detected.

HV Component Failure by Lead Model

• Evolution to cable design associated with improved lead performance

www.bostonscientific.com

Medtronic Transvene

Ellenbogen et al. JACC Jan 1, 2003

Medtronic Fidelis

High voltage performance not broken out in PPR data

Medtronic Fidelis

• HV Failures: 5% of overall failures in series

Circulation. 2011;123:358-363

Medtronic Fidelis


• HV Failures: 6.1% of overall failures in RPA

Medtronic Fidelis



• Conductor fracture (abrupt >100 Ω) in all RPA

Medtronic Fidelis

Medtronic Field Communication April 2011



• Conductor fracture (abrupt >100 Ω) in all RPA

• Failure of pace-sense electrode predicts failure of high voltage conductors

Medtronic Field Communication April 2011

Medtronic Fidelis

Conductor fracture,New pace/sense lead 5076

SVC cable fracture

RV cable fracture

St. Jude Riata/Riata ST

WSJ.com

Cardiobrief.org

Riata High Voltage Shock Delivery

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

ICD Can

Riata HV Insulation Shorts

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

z12

ICD Can

3

3

RV HV cable/coil

shorts to

SVC cable/coil or can


SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

1) RV HV cable to can

z1

ICD Can

Programming the can out of the system may mitigate (if dual coil lead)


SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

1) RV HV cable to can2) RV HV cable to SVC cable or coil

2

ICD Can

Programming SVC Coil out of system may mitigate failure


SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

1) RV HV cable to can2) RV HV cable to SVC cable or coil3) RV Ring P/S cable to RV HV cable

and RV ring to can

ICD Can

3

3

Other variations of #3 exist with alternative return circuit

Detection of Riata/ST Failures

• Earlier generation ICDs (Atlas/Epic) do not have automatic HV testing

High voltage testing with Atlas/Epic must be performed manually


• Earlier generation ICDs do not have automatic HV testing (Atlas/Epic)

• Automated HVLI testing in later generations

St. Jude Medical. Riata Lead Summit 1/12


• Earlier generation ICDs do not have automatic HV testing (Atlas/Epic)

• Automated HVLI testing in later generations



Riata/ST High Voltage FailureWhat do the large trials tell us?

Trial #patients #/% ElectricalFailures

#/% of electrical that are HV

VA1 1403 47 (3.4%) 3 (6.3%)

Canadian2 4358 201 (4.6%) ?? >= 1 HV failure

US Multicenter3 1081 67 (6.2%) 3 (4.4%)

St. Jude Riata LES4 776 10 (1.3%) 5 (50%)

1. Sung et al. Heart Rhythm 2012 9:1954-19612. Parkash et al. Heart Rhythm 2013 10: 692-6953. Abdelhadi et al Heart Rhythm 2013 10: 361-3654. Hayes et al. Heart Rhythm 2013 10: 1778-1782

50% of detected failures were in HV circuit

Heart Rhythm 2013 10: 1778-1782

• Prospective 782 pts: followed avg 9.8 months • Baseline fluoroscopy and serial electrical testing• Average lead age--Riata 6.5 yr, Riata ST 4.8 yr• “Potential” HV failure defined as

• HVLI change >25 Ωor

• HVLI >125Ω or <20Ω • 5 of 10 adjudicated electrical failures were HV• Additional 4 leads had HVLI change >25 Ω but

adjudicated as normal function

Danish Riata Registry

• 295 mature Riata Leads (5.1 +/- 1.1 yr)

• Baseline fluoro, prospective F/U (1.1 yr)

• 6.5% electrical abnl (21.9% w/EC, 5.3% wo/EC)

Heart Rhythm, In Press

- Low incidence of HV failures (high impedance)

- No instances of HV insulation (low impedance) failure detected

- No low impedance pace failures in EC group

Only 51% of leads had high voltage testing performed

How Well are we Detecting Riata High Voltage Failures?

• 77 year old man, ischemic cardiomyopathy• EPIC DR ICD with Riata 1580, externalized, No HVLIs• Gen change to Fortify DR. HVLI normal at 39 Ω• VF induced with 1 J T shock• 20 J shock failed, external defib, ICD system error• HVLI repeated, still normal at 35 Ω• 20 J shock failed, external defib, ICD system error• HVLI now <10 Ω, no sensing issues

Short evident between SVC coil and RV shock cable

Doshi Case - Riata HV Insulation Short #2

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

RV HV cable to SVC coil short

2

ICD Can

Lead failure repeatedly not evident by low voltage testing

Tip of the Iceberg?

• 3 similar case reports in the literature1,2,3 – HV failure at shock with normal low voltage testing

• Hauser analysis of MAUDE database4 reported 91% of Riata related deaths were due to HV failure

• Hauser reported abrasion failures of Durata5

1) Leong et al, PACE, June 20122) Shah, et al, JCE January 20133) Marenco PACE 20134) Hauser Heart Rhythm August 20125) Hauser Europace, February 2013

Thomas Hawk: Flikr.com shared under Creative Commons license

Tip of the Iceberg?“Crash Testing”

AHA Scientific Sessions 2012

• 90 Riata/ST pts underwent fluoro and HV shock• 51% externalized conductors• 9% (8 pts) failed shock testing (8/9 not externalized)

• HV failure defined as failure to induce/sense/shock VF

Tip of the Iceberg?“Crash Testing”

HRS Sessions 2013

• 289 Riata/ST patients evaluated• Mean implant time 5.7 years• Externalization by CXR: 13.1% Riata, 4.8% Riata ST• 116 patients underwent DFT test at max output• 1 Riata patient (1%) failed to rescue with initial shock

(HV <10%)

RV ring P/S Cable

Riata Evolution to Durata

SVC HV Cable

RV HV Cable

RV tip filament


and RV ring to can

z12

3

ICD Can

3

Optim outer insulation added with Durata

Durata ICD Lead Performance

Durata ICD Lead Performance

• Cairns et al report results of three active St. Jude managed registries on Optim ICD leads

• 11,016 leads

• Mean Follow up 3.2 years

• Independent review by Canadian Investigators

• 51 mechanical failures (0.46%), 99% survival

• No externalized leads

Criticisms of Optim ICD Lead Registry

• 22.9% drop out due to missing data

• 3.3% of leads taken out of service seems high compared to 0.46% failure. Why?

• 19.2% death or transplant. No report of post mortem interrogations. No way to exclude lead failure as cause of death.

• 39% of the leads with mechanical failure had returned product analysis. Is this too high?

Durata High Voltage Failure

• 55 yo male with Current DR, Durata lead, 12/09• NS VF episode detected, therapy diverted. EGM

shows noise on RV P/S and RV HV, not on RA• To ER w/vibrating ICD in backup mode. HV

therapies disabled and no programmability

PACE. September 2013


• In lab: Normal sensing/threshold/Ω/fluoro• No noise could be reproduced, appearance OK• New Fortify DR ICD:

• 20 J synchronized test shock successful• VF, 36 J shock failed, audible “pop”• Still in VF, 40J shock failed, backup mode• New lead & 2nd PG placed, VF test successful


RV coil-can

A sense

RV sense

Simultaneous noise on RV shock coil-can and RV sense electrodes with normal atrial sensing

RV shock coil to RV cable short

Durata High Voltage Failure #3

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament


and RV ring to can

ICD Can

3

3

Optim Insulation


https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/Detail.cfm?MDRFOI__ID=3669333

• 49 yo woman w/hypertrophic cardiomyopathy

• Current DR with Durata 7120 placed 7/08

• Normal office follow up (low and high voltage)

Heart Rhythm, October 2014


• 12/13, arrest at work. 15 min bystander CPR, Squad shocked VF multiple times, hypothermia

• ICD evaluation: – HV impedance <10 Ω (vector not specified)

– HVLI and pace/sense evaluation normal

• Durata Lead extracted

• No visual or fluoroscopic abnormalities in lab

• New Medtronic ICD lead and PG placed


Durata HV Failure

Electrically silent inside out abrasion of Durata RV conductor cable under SVC coil near fatal shock failure

Personal communication and chart review, M. Gupta MD. The Christ Hospital, Cincinnati, OH

Durata HV FailureElectrically silent inside out abrasion of Durata RV

conductor cable under SVC coil near fatal shock failure


RV conductor CableSVC Coil

Durata High Voltage Failure #2

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

RV HV cable to SVC Coil

ICD Can

2

New St Jude System Enhancements

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

2

ICD Can

3

1

A) Parylene Coating on ICD can with Elipse PGB) Additional Optim layer from proximal end to

SVC coil with Optisure LeadC) Dynamic Tx provides shock vector switching

with detection of insulation breach

3

High Voltage ICD Lead Failure

• Underappreciated and potentially fatal

• Can present with no change in painless HV impedance or any other parameters measured in ICD follow up

• Presentation varied and at times very complex

• Existing means of detection are inadequate

• Open question: Do we need to change our follow up strategies?

High Voltage ICD Lead FailureSuggestions

• We need to encourage post-mortem interrogation ICD patients. This should be required in registries and pre market trials.

• Support investigation of St. Jude leads for high voltage performance - “Crash Test” trial.

• Encourage a protocol for assessment of St. Jude ICD leads at device replacement.

Thank you!

Backup Slides

Riata Failures in Danish Registry

Larsen et al HRS abstract 2014

• No low impedance high voltage failures in EC or no EC groups• Low impedance failure in pace/sense electrode seen only in no EC group

EC= Externalized Conductors

Thomas Hawk: Flikr.com shared under Creative Commons license

Airbag Reliability

• 100 drivers

– 10 get in accident

• 9 effective airbag deployment

• 1 driver dies with ineffective airbag

• What is the airbag failure rate?

– 1% or 10%?


SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament


and RV ring to can

z12

ICD Can

3

3

RV ring P/S Cable

Riata Evolution to Durata

SVC HV Cable

RV HV Cable

RV tip filament


and RV ring to can

z12

3

ICD Can

3

Optim outer insulation added with Durata

New St Jude System Enhancements

31

SVC HV Cable

2 RV HV Cable

RV ring P/S Cable

RV tip filament 3

ICD Can

A) Paraylene Coating on ICD can with Elipse PGB) Additional Optim layer from proximal end to

SVC coil with Optisure Lead

1) RV HV cable to can2) RV HV cable to SVC cable or coil3) RV Ring P/S cable to RV HV cable and RV

ring cable to can

Riata HV Insulation Shorts #3A

3

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament


and RV ring to SVC coil/cable

ICD Can

3

Riata HV Insulation Short #3b

33

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament


and RV ring to RV tip and RV tip to can

ICD Can

3

Mitigation of Failure #2 with SVC Reprogramming

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

RV HV cable to SVC cable or coil

2

ICD Can

Mitigation of Failure #2 with SVC reprogramming

SVC HV Cable

RV HV Cable

RV ring P/S Cable

RV tip filament

RV HV cable to SVC cable or coil

2

ICD Can

SVC Programmed off Shorted SVC current blocked at can.Shock impulse arrives at heart, grounds to can.

JCE January 2013

• 72 year old with CAD, sustained VT• ICD 2004: 1580 Riata. Gen change 2009 Current Plus,

VF induced & terminated with 20 J shock • 2012 SVT episode. 25 J charge but shock truncated

with HV Ω <10J. SVT terminated spontaneously• All HV parameters normal – HVLI 44Ω

JCE January 2013

• Fluoro showed externalization between shock coils• DFT test: 20 J shock truncated with HV <10 Ω. Pt

externally defibrillated

Riata/ST High Voltage FailureWhat do the large trials tell us?

• VA Trial Sung et al– Total electrical Failure 3.7% (47/1403). HV failure 3 (6%/0.2%)*

* (% of population/% of failed leads)

icd system high voltage component failure (presented to fda)

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