Defibrillation-proof type CF applied part (heart in a square with side marks)

The standard’s wording, as the sources below reproduce it:

“To identify a defibrillation-proof type CF applied part complying with IEC 60601-1.”

IEC 60417-5336 · IEC 60601-1, Table D.1, symbol 27

What it means for you

An applied part is the part of the equipment that touches the patient — an electrode, a sensor, a probe. The letter is its protection class against electric shock under IEC 60601-1. This is a type CF part (the class for direct heart contact) that is also designed to withstand a defibrillator shock given to the patient — typical of ECG inputs on monitors and defibrillators.

Whether a device is right for you is a question for your pharmacist, nurse or doctor.

What it looks like: The type CF heart in a square with a short vertical bar and a stub line on each side.
Where you see it: On medical electrical equipment and its accessories — on the cable, the sensor, the connector socket or the rating plate — not on the sterile box. IEC 60601-1 Table D.1 lists it.
Other names: defib-proof CF; heart in a box with paddles

What it does not tell you

It does not mean the equipment delivers a shock, and it does not mean staff can touch the patient during a shock.

Often confused with

Type CF applied part (heart in a square)IEC 60417-5335

To identify a type CF applied part complying with IEC 60601-1.

More symbols in “A person or a heart”

Patient number (person with #)ISO 15223-1:2021, 5.7.1 Patient name (name card)ISO 15223-1:2021, 5.7.2 Patient identification (person with ?)ISO 15223-1:2021, 5.7.3 Health care centre or doctor (doctor with a cross)ISO 15223-1:2021, 5.7.5 Type B applied part (figure)IEC 60417-5840 Type BF applied part (figure in a square)IEC 60417-5333 Defibrillation-proof type B applied part (figure with side marks)IEC 60417-5841 Defibrillation-proof type BF applied part (figure in a square with side marks)IEC 60417-5334

Sources

IEC 60417 and IEC 60601-1 are paid standards, so the wording above is quoted as 4 publishers’ public documents reproduce it; our drawing is not the IEC artwork. Each was fetched and read on the date shown:

Boston Scientific: Symbols Glossary — IEC 60601-1 Table D.1, symbol 27 “Defibrillation-proof type CF applied part — To identify a defibrillation-proof type CF applied part complying with IEC 60601-1.” Checked 2026-09-28.
NE Scientific: Master Symbol Glossary (CTF-100011 Rev 01) — Shows the mark for IEC 60417-5336, same description. Checked 2026-09-28.
Hillrom: Symbols Glossary (80022945 Ver. J) — Lists “Defibrillation-proof type CF applied part”, IEC 60417-5336. Checked 2026-09-28.
Ethicon: Symbols glossary (100584677 Rev.8) — Shows the heart in a square with side marks for IEC 60417 reference 5336. Checked 2026-09-28.

Plain-language parts are in our own words; quotations are the sources’ wording.