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ISO 27185:2012 — Cardiac Defibrillators — Essential Performance and Safety Symbols
Standardized symbols for cardiac rhythm management device labelling
1. Scope and Purpose of Symbol Standardization for Cardiac Devices
ISO 27185:2012 specifies requirements for symbols used on cardiac rhythm management (CRM) device labels and the information to be supplied with these devices. The standard addresses the critical need for globally harmonized symbols that convey essential safety and usage information for implantable cardiac devices including pacemakers, implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices. It was developed by ISO/TC 150/SC 6, Active implants, to overcome the challenges of multilingual labelling in a global medical device market where manufacturers must comply with diverse regulatory requirements across many countries and languages.
Standardized symbols eliminate language barriers in medical device labelling, allowing manufacturers to use a single label design worldwide while ensuring that patients and healthcare providers can understand critical safety information regardless of their native language. The standard provides a comprehensive set of symbols covering device identification information such as manufacturer name and model number, physiological effects including heart rhythm and defibrillation indications, implantation guidance with anatomical location references, operational parameters like battery status and programmability, electromagnetic compatibility warnings including MR Conditional conditions and radio frequency interference precautions, and disposal instructions for environmental compliance. Each symbol has a precisely defined graphical representation and unambiguous meaning validated through user comprehension testing.
Standardized symbols eliminate language barriers in medical device labelling, enabling manufacturers to use a single label design worldwide while ensuring patients and healthcare providers can understand critical safety information regardless of their native language. This reduces labelling costs by 30 to 50 percent for global manufacturers.
| Symbol Category | Examples | Primary Purpose | Target Audience |
|---|---|---|---|
| Device Identification | Manufacturer logo, model number, SN | Traceability | Clinicians, regulators |
| Physiological | Heart symbol, defibrillation effect | Clinical guidance | Physicians, patients |
| Implantation | Implant location, lead orientation | Surgical guidance | Surgeons |
| Operational | Battery status, programmability mark | Device management | Clinicians, patients |
| EMC and MR | MR Conditional, RF warning signs | Safety warnings | All users |
| Disposal | Recycling logo, WEEE compliance | Environmental | Hospitals, patients |
2. Requirements for Symbol Usage and Validation
The standard establishes rigorous requirements for symbol adoption and usage. Any new symbol proposed for inclusion must undergo a formal validation process including comprehension testing with representative users from the target audience. The validation protocol specifies a minimum acceptable comprehension rate of 85 percent for each symbol tested, with specific pass-fail criteria depending on the criticality of the information being conveyed. Safety-critical symbols that communicate warnings about potential death or serious injury must achieve the highest level of validation — if such a symbol fails to meet comprehension requirements, it must be redesigned and re-validated before it can be used on any device label.
The standard addresses all aspects of symbol presentation including minimum size requirements ensuring legibility under typical viewing conditions, colour usage constraints recognizing that some users may have colour vision deficiencies, placement requirements ensuring symbols appear in logical locations on the device or packaging, and durability requirements ensuring symbols remain legible throughout the expected device lifetime. For implantable CRM devices, the expected lifetime can exceed 10 years, and labels must remain readable for the entire duration. The standard references ISO 15223-1 for general medical device symbol requirements with additional provisions specific to CRM devices.
Symbols with safety-critical meanings must achieve the highest validation standards with a minimum 85 percent comprehension rate. If a symbol fails to meet comprehension requirements, it must be redesigned and re-validated before inclusion. Manufacturers cannot simply add clarifying text — the symbol itself must be intuitively understandable without additional explanation.
The standard includes detailed specifications for each approved symbol including the exact graphical representation, the precise meaning in text form, and examples of appropriate usage contexts. Symbols are organized by functional category with cross-references to related symbols for easy navigation. The standard also addresses symbol combinations — when multiple symbols are placed together, their arrangement must not create confusion or suggest relationships that do not exist. For example, a prohibition symbol (circle with diagonal line) must be clearly associated with the specific activity being prohibited, not ambiguously positioned near multiple symbols.
3. Engineering Insights for Medical Device Labelling
Medical device labelling is a critical component of patient safety, yet it receives less attention than device design and manufacturing in many engineering programmes. For CRM devices, labels must communicate complex technical information to diverse audiences including implanting surgeons with detailed anatomical knowledge, cardiologists managing long-term device therapy, clinical nurses performing routine device checks, patients living with the implanted device, and family members who may need to assist in emergencies — each group has different levels of technical expertise and different information needs. A well-designed symbol system serves all these audiences efficiently through intuitive graphical communication.
The standard includes informative annexes with practical examples of symbol usage on device packaging, physician manuals, patient identification cards, and hospital information systems. The graphical symbol system for implantable cardiac devices uses a consistent design language with common elements such as the heart shape as a universal identifier, lightning bolt symbols for electrical shock or defibrillation indications, anatomical references such as the thoracic cavity outline, and internationally recognized hazard symbols. Users quickly learn to recognize these visual elements, making the symbol system increasingly effective as familiarity grows. The validation annex provides insight into the testing methodology used to confirm symbol comprehension.
The use of standardized symbols consistent with ISO 27185 reduces labelling costs by 30 to 50 percent for global device manufacturers by eliminating the need for multilingual text translations while improving patient safety through consistent, validated graphical communication. Additional benefits include reduced label size, simplified regulatory submissions, and faster market access in new countries.
The standard’s requirements are designed to be complementary with regional regulatory requirements including the European Medical Device Regulation (MDR) and US FDA labelling requirements. Many regulatory authorities accept symbols from recognized international standards as meeting their labelling requirements, provided the symbols are used according to the standard’s specifications. The bibliography identifies other relevant symbol standards applicable to specific device types or situations, such as symbols for defibrillator pads placement and symbols for remote monitoring status. Manufacturers should incorporate symbol requirements early in the device development process rather than treating labelling as an afterthought — label space requirements can significantly impact packaging design and device housing dimensions.
FAQs
Q: Are ISO 27185 symbols mandatory for all cardiac rhythm management devices?
A: In most regulatory jurisdictions, symbols from recognized international standards are accepted if they meet validation requirements. However, specific regulatory requirements vary by country and region. Manufacturers should consult with their regulatory affairs teams.
A: In most regulatory jurisdictions, symbols from recognized international standards are accepted if they meet validation requirements. However, specific regulatory requirements vary by country and region. Manufacturers should consult with their regulatory affairs teams.
Q: What happens if a symbol is not understood by healthcare providers during validation?
A: If comprehension testing shows understanding below the minimum 85 percent threshold, the symbol must be redesigned and re-validated. Simply adding explanatory text is not an acceptable solution — the graphical symbol itself must be intuitively understandable.
A: If comprehension testing shows understanding below the minimum 85 percent threshold, the symbol must be redesigned and re-validated. Simply adding explanatory text is not an acceptable solution — the graphical symbol itself must be intuitively understandable.
Q: Can manufacturers create their own proprietary symbols for CRM devices?
A: Yes, but proprietary symbols must also meet the rigorous validation requirements of ISO 27185 and should be harmonized with the established symbol system to maintain consistency across the device ecosystem.
A: Yes, but proprietary symbols must also meet the rigorous validation requirements of ISO 27185 and should be harmonized with the established symbol system to maintain consistency across the device ecosystem.
Q: Does ISO 27185 cover symbols for external defibrillators used in emergency settings?
A: The scope is limited to cardiac rhythm management devices, primarily implantable devices such as pacemakers and ICDs. External defibrillators, including AEDs, are covered by other standards such as IEC 60601-2-4.
A: The scope is limited to cardiac rhythm management devices, primarily implantable devices such as pacemakers and ICDs. External defibrillators, including AEDs, are covered by other standards such as IEC 60601-2-4.
