New Information on Pacemakers

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Technical Instructor
Scuba Instructor
Reaction score
Boulder, CO
# of dives
1000 - 2499
I was doing some research on Pacemakers, and I found people providing advice that was all over the board, including on threads in this forum and in many other places on the Internet. I found people saying there were restrictions anywhere from 50 feet to 165 feet, with 100 feet being the most common response. I read stories about people being prohibited from diving at all or beyond a very shallow depth by dive operators.

In my research, I sent an inquiry to one of the leading manufacturers, St. Judes. They sent me an immediate response that provided an official statement that is different from everything else I have read.

Here is what they said in its entirety.

Scuba diving, Hyperbaric oxygen therapy (HBOT), and other activities that increase or decrease pressure gradients, can have an effect on the function of pacemakers and implantable cardioverter defibrillators (ICDs).

While interference with normal device operation of an implanted device as a result of scuba diving or HBOT is not likely, the most probable outcome would be a temporary effect on the device’s rate-adaptive pacing function. St. Jude Medical rate responsive pacemakers implanted before 1999 (such as the Synchrony®, Paragon®, and older Trilogy® pacemakers) employ a piezoelectric crystal activity sensor that is mounted on the internal surface of the can. Increases in atmospheric pressure can cause flexing of the can, and therefore may cause an increase of sensor driven rate possibly up to the programmed maximum sensor rate. Newer devices utilize an internal accelerometer that is not as susceptible to these pressure changes and are much less likely to respond to pressure changes during diving or HBOT.

St. Jude Medical pacemakers and ICDs have been tested to an absolute level of 7 atmospheres (6 atmospheres gauge pressure, or approximately 88 psi, at sea-level) with no effect on device function. These tests showed that, if properly administered, HBOT should not interfere with or cause permanent damage to a device. In addition, St. Jude Medical has not received any reports of a pacemaker or ICD being adversely affected by scuba diving or HBOT.

Potential Effects
In the unlikely event that a St. Jude Medical device exhibits a rate increase up to the maximum sensor rate upon exposure to elevated pressure, the rate will return to the base rate as the pressure stabilizes. If the increase in pressure is gradual, the rate will change gradually and may stabilize at a rate higher than the base rate.

• Pacemakers should not be exposed to absolute pressures above 7 atmospheres or the equivalent depth of 198 feet of saltwater. (6 atmospheres above ambient sea-level pressure).
• ICDs should not be exposed to absolute pressures above 7 atmospheres or the equivalent
depth of 198 feet of saltwater. (6 atmospheres above ambient sea-level pressure).​
If you have any questions on this topic, please contact St. Jude Medical Technical Services at 800-722-3774​

New model (after 1999) St. Jude Pacemakers are suitable for use up to 7 atmospheres, or 198 FSW.

I strongly suggest that anyone who may be given unreasonable restrictions for diving contact the manufacturer and get such a statement.
This is superb--thanks BJ.

I find this info is quite valuable and commend St. Jude Medical, Inc for researching their devices such that they can responsibly make such specific statements.

While I certainly do not know, I strongly suspect that some other manufacturers of pacemakers and implantable cardioverter defibrillators would not be able to provide such a statement as they have not done the necessary study.


For anyone getting or replacing a pacemaker, it's good to get this info in advance. As mentioned, the level of testing done will vary by manufacturer and model type. Some do not test beyond a few atmospheres, and none will make a recommendation beyond what it actually tested. For my first one, I talked to one of the engineers and chose a model based on his recommendation.

Also, it's good to carry a letter from your cardiologist, stating that it will not interfere with your diving activities. A statement from the manufacturer pertains to the device. One from your doctor adds you into the equation. I've been carrying a letter for 14 years, though no one has ever asked to see it. In that time, I've done about 1,000 dives and have never encountered a problem or restrictions.

It's always good to state you have a pacemaker [just in case], then confidently say that it does not interfere with your diving in any way. The issue with dive operations is liability.
Good info John, thanks for posting.
Subjects wanted for a research study
Investigation of diving experience of divers with implanted cardiac devices

Divers Alert Network (DAN) is conducting a research study about divers with an implanted pacemaker or defibrillator who are choosing to dive with or without medical clearance. The study consists of an on-line survey which takes about 10 minutes to complete and possible follow-up interview if additional clarifications are needed.
If this pertains to you, please contact DAN Research (919-684-2948 or will not be compensated for participation.

IRB# 017-13 Expiry date: 6/05/2014

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