Biomedical Engineering Reference
In-Depth Information
In pacemakers or in terms of the ICD pacing function, a
strong EMI may result in the following situations [17]:
Pacing inhibition
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ISO 14708-6, Implants for surgery - Active implantable
medical devices - Part 6: Particular requirements for
active implantable medical devices intended to treat
tachycardia (including implantable de fi brillators) and the
European standards EN 45502 series:
EN 45502-1, Active implantable medical devices - Part 1:
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Switching to asynchronous pacing
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Tracking the interfering rhythm to ventricle pacing
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Lead system-induced current
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Switching of a magnetic switch
General requirements for safety, marking, and informa-
tion to be provided by the manufacturer
EN 45502-2-1, Active implantable medical devices -
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Heating of pacing leads
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Damage to device electronics
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In ICDs, the following situations may also occur [72]:
Switching off tachycardia therapy
Part 2-1: Particular requirements for active implantable
medical devices intended to treat bradycardia (cardiac
pacemakers) [ 17 ]
EN 45502-2-2, Active implantable medical devices - Part
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Undesirable shock as a consequence of the detection of an
interfering signal as tachycardia
The danger of EMI effects on a patient depends on the
period of exposure, distance from the source, and the posi-
tion of a patient or implanted system in reference to the
field source. It is almost impossible to estimate in advance
the possible effects of EMI on the operation of pacing
technology.
Possible significant EMI sources include:
High voltage lines
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2-2: Particular requirements for active implantable medi-
cal devices intended to treat tachycardia (includes implant-
able de fi brillators) [ 72 ]
Corresponding standards in the ISO and EN systems are
practically the same and establish the same technical require-
ments and reference values for testing the safety of implant-
able devices and their components. All designated pacing
technology tests are specified for devices at 37 ± 2 or
37 ± 5 °C. Because established designs are not temperature
sensitive within such a temperature range, this is believed to
be sufficient to validate an implantable device at thermal
equilibrium after implantation.
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Radio communication devices (transmitters, amplifiers,
radar)
Arc welders
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Electric induction devices
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Electric manual tools
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Electronic article surveillance systems
14.2.1 Packaging, Leakage Currents, Dissipating
Heat, and Power Source Requirements
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Electric furnaces
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Vehicle alternators
The outer packaging of implantable system components
shall contain information and parameter values for the pur-
pose of complete identification, and a notification that ICDs
are always supplied with inactivated tachycardia treatment.
Furthermore, the designation of connector types and dimen-
sions must also be included so that compatible system com-
ponents may be identified without having to open the sterile
packaging. As far as pacemakers are concerned, information
on the most comprehensive pacing mode available and the
mode set on dispatch must be provided. On ICD packaging,
available tachycardia therapies must be listed, and a warning
of the necessity of inactivating the tachycardia treatment
during surgical interventions must be given.
The accompanying documentation must contain informa-
tion on the average estimated longevity (in years) of the
device. The longevity should depend on the total number of
maximum-energy shocks. All packages containing sterile
material must carry information on the expiration date in the
year-month-day sequence. Provided that expected applica-
tion of an AIMD implantable component closed in sales
packaging requires the component to be connected to
other devices or accessories not contained in the packaging,
the sales packaging must specify the connector type
14.2
Technical Standardization and Pacing
Technology Tests
A technical standard is a documented requirement concern-
ing operational, functional, or performance properties, pro-
mulgated by an official body, which must be met by products
or services for an intended purpose. Compliance with the
technical standards can be mandatory or voluntary, depend-
ing on the country. This has changed during the history of
implanted devices. Nevertheless, standards establish the ref-
erence values and safety criteria or are required in public ten-
ders, and compliance with the technical standards can affect
the rollout of a product (declaration of conformity).
The basic technical standards covering implantable pac-
ing technology are international standards in the International
Organization for Standardization (ISO) 14708 series:
ISO 14708-1, Implants for surgery - Active implantable
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medical devices - Part 1: General requirements for safety,
marking and information to be provided by the
manufacturer
ISO 14708-2, Implants for surgery - Active implantable
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medical devices - Part 2: Cardiac pacemakers
