Presentation: Pacemaker investigation

Pacemaker Investigation An example of Medical Device Testing at the TGA

Arnie Riedl Biomaterials & Engineering Section, Office of Laboratories and Scientific Services, TGA Australian Biomedical Engineering Conference

20 August 2014

Office of Laboratories & Scientific Services Testing at the TGA

• Part of the post-market monitoring & compliance system

• Risk-based

• Results in regulatory outcomes

Pacemaker Investigation 1

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Office of Laboratories & Scientific Services Types of testing

• Responsive eg. Adverse event investigations

• Programmed Testing eg. Check compliance with technical standards – Surveys of product ranges to check for compliance with required standards – Lot release review of manufacturing and test data for marketing of individual batches of vaccines and

selected biological medicines

• Maintenance & External • Research and development of technical and regulatory standards and test methodologies

2 Pacemaker Investigation

3 Pacemaker Investigation 3

Type of testing

Responsive Problem reports

Programmed Proactive compliance testing

Maintenance QA, method development accreditation, standardisation

External WHO, other government, regional support

Type of testing (2012)

Safeguarding public health

Responsive 25%

Programmed 60%

Maintenance 10%

External 5%

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Programmed Testing • Mandatory reporting by sponsors • Voluntary reporting by users etc • Testing projects chosen from:

– statistical analysis – specific events – international data

• Examples: – Ear thermometer accuracy – Surgical (vaginal) meshes cytotoxicity – AEDs time to deliver therapy – Wheat bag flammability


Requires adverse event reporting!

Responsive Testing • Investigate the cause of specific events • Examples:

– Injuries from crutches that broke – Head injuries from a wheelchair that

tipped over – Fire in a battery powered wheelchair – Death while wearing a pacemaker


Testing in OLSS • Done within a rigorous framework defined by our quality system • Some tests are NATA accredited (eg, examination gloves & condoms) • To local & international standards where possible • Other testing done to meet the needs of a specific incident

• Regulatory outcomes are more likely with more evidence – take away message is to submit more adverse event reports!


Adverse Event – Pacemaker Investigation • A man passed away with a pacemaker implanted. The device was sent to the TGA to determine if

the pacemaker was working appropriately and if it may have played a role in the death of the user.


Receipt • Incident logged into database

• Pacemaker sent for cleaning!


Device


Model

Serial #

Manufacturer

Device


Electrical Testing – ISO 14708-2 • HP 54502B 200MHz Analog CRO • Fluke SigmaPace 1000 External Pacemaker Analyzer


Measured bipolar output – 1000W load • 1.5V Peaks

• 60 malformed pulses

per minute


Possible Issues • Lack of a square wave output may mean the battery is depleted

• Discolouration on back of device indicates significant localised

heating

• Has the device short-circuited and overheated inside the patient??


Coroner Images • Supported our hypothesis

of overheating


Coroner Images • Supported our hypothesis

of overheating


Canberra Imaging - Mammogram


Canberra Imaging – Standard X-ray


Canberra Imaging – CT Scan


• Computerised (Axial) Tomography (CT) Scan of pacemaker.

Image Analysis


• Battery is not at location of overheating

• No internal damage evident

Mammogram

X-Ray

Manufacturer’s documented x-ray image

Canberra Hospital – Pacemaker Interrogation • The device was initially hard to

interrogate (comms problems)

• Cardiologist advised discolouration wascaused by external defibrillation (typical of devices subjected to shocks from external defibs)

• Battery life “OK“ (over 7 years remaining)


Canberra Hospital – Pacemaker Interrogation • Analysis of stored data did not

provide any information indicating abnormal device behaviour

• Best data was possibly approximate date of death (impedance increases)


Electrical Testing – back to the drawing board • The device was programmed to

Unipolar Mode


Electrical Testing


• Nice square wave apparent

Electrical Testing – Final Results Programmed Mode SSIR

Amplitude 2.4 V

Refractory Period 300 ms

Rate 60 ppm (rate adapting)

Width 0.40 ms

Energy

Battery Unipolar

Connector N/A


Electrical Testing – Final Results Programmed Specifications Mode SSIR SSIR

Amplitude 2.4 V 2.4 +0.1/-0.5V

Refractory Period 300 ms 300 +10/-20 ms

Rate 60 ppm (rate adapting) 60 ±1.5 min-1

Width 0.40 ms 0.42 ± 0.02

Energy

Battery Unipolar Bipolar/ Unipolar

Connector N/A IS-1


Electrical Testing – Final Results Programmed Specifications Measured Mode SSIR SSIR SSIR

Amplitude 2.4 V 2.4 +0.1/-0.5V 2.08 V

Refractory Period 300 ms 300 +10/-20 ms 300 ms

Rate 60 ppm (rate adapting) 60 ±1.5 min-1 60.0 ppm

Width 0.40 ms 0.42 ± 0.02 0.424 ms

Energy 3.79 mJ

Battery Unipolar Bipolar/ Unipolar Unipolar

Connector N/A IS-1 OK


Electrical Testing – Final Results Programmed Specifications Measured Manufacturer Mode SSIR SSIR SSIR SSIR

Amplitude 2.4 V 2.4 +0.1/-0.5V 2.08 V 2.11 V

Refractory Period 300 ms 300 +10/-20 ms 300 ms

Rate 60 ppm (rate adapting) 60 ±1.5 min-1 60.0 ppm 60 ppm

Width 0.40 ms 0.42 ± 0.02 0.424 ms 0.43 ms

Energy 3.79 mJ 3.5 mJ

Battery Unipolar Bipolar/ Unipolar Unipolar 2.79 V

Connector N/A IS-1 OK OK


Electrical Testing – Final Results Programmed Specifications Measured Manufacturer Result Mode SSIR SSIR SSIR SSIR OK

Amplitude 2.4 V 2.4 +0.1/-0.5V 2.08 V 2.11 V OK

Refractory Period 300 ms 300 +10/-20 ms 300 ms OK

Rate 60 ppm (rate adapting) 60 ±1.5 min-1 60.0 ppm 60 ppm OK

Width 0.40 ms 0.42 ± 0.02 0.424 ms 0.43 ms OK

Energy 3.79 mJ 3.5 mJ OK

Battery Unipolar Bipolar/ Unipolar Unipolar 2.79 V OK

Connector N/A IS-1 OK OK OK


Electrical Testing – Final Results Programmed Specifications Measured Manufacturer Result Mode SSIR SSIR SSIR SSIR OK

Amplitude 2.4 V 2.4 +0.1/-0.5V 2.08 V 2.11 V OK

Refractory Period 300 ms 300 +10/-20 ms 300 ms OK

Rate 60 ppm (rate adapting) 60 ±1.5 min-1 60.0 ppm 60 ppm OK

Pulse Width 0.40 ms 0.42 ± 0.02 0.424 ms 0.43 ms OK

Energy 3.79 mJ 3.5 mJ OK

Battery Unipolar Bipolar/ Unipolar Unipolar 2.79 V OK

Connector N/A IS-1 OK OK OK


Pacemaker Investigation – concerns • Pulse width measured at 0.424 ms. • Programmed settings 0.40 ± 0.02 ms (ISO Standard gives a 5% tolerance) • Documentation states the pulse width is 0.42 ± 0.02ms

• Manufacturer responded that the programmer output is only accurate to 1 decimal

place, although it displays 2 decimal places • TGA though this was potentially misleading • BUT has no real clinical relevance and no action recommended


Pacemaker Investigation – Conclusions • Patient’s symptoms had been ventricular fibrillation

• A known medical complication of pacemakers is the small risk of pacemaker-induced arrhythmias including ventricular fibrillation

• At the time of testing, the device had performed normally

• Nothing conclusive could be said about its performance around the time of the patient’s death other than that it was unlikely to have played a role in its cause


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PLEASE REPORT THE INCIDENT…

it could save a life!

http://www.tga.gov.au/safety/[email protected] 1800 809 361

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Presentation: Pacemaker investigation