International Travel / TZ Change and settings

Your EP-team can do this for you

by crustyg - 2024-09-30 02:19:29

Only someone with a device programmer can change the TZ setting - at least for BostonSci devices.

It's theoretically possible for a Bluetooth-smartphone-app connected device to permit a TZ update, but as this is very close to 'reprogramming' the device the vendor might have chosen to make it EP-team only.

Ask your EP-techs.

Interesting

by piglet22 - 2024-09-30 05:43:30

Most modern devices will have a Real Time Clock incorporated. This is for logging events and programmed settings like sleep or possibly automatic data transmissions.

Quite often this will be a separate chip on the PM board. An example is Maxim (Dallas) DS3231.

It had never occurred to me, despite using a lot of things that rely on time and regular changes like Daylight Savings Time, the change that many countries adopt like the UK BST/GMT, that it could be relevant to pacemakers.

USA will have time zones from east coast to west coast, all different.

An easy way to automate the change is to use internet time to synchronize a device local time update and most computers and connected devices like mobile phones update the DST in March and October.

An unconnected device would have to have it's local time changed as it crossed time zones.

As a very infrequent traveller, I've never given crossing time zones or even DST a second thought where PMs are involved, but clearly the PM clock needs to take into account local time if events are recorded.

A patient who changes time zones might experience an event locally, say in New York,but if the PM clock hasn't been updated,but would log it 5 hours different for a UK traveller. It could be important to sleep related settings.

The advert of Bluetooth enabled PMs could change all that and a device could be automatically updated with internet time.

I have a special interest in RTCs and monitor them regularly against time standards like the National Physical Laboratory radio time signal to check their accuracy.

In my experience, a free-running RTC loses or gains seconds or minutes over say a month and if not corrected, in the lifetime of a PM, say 10 years, it could be a significant error.

An interesting topic.

My Perspective on PM Internal Timekeeping

by DoingMyBest - 2024-09-30 09:44:19

My St. Jude/Abbott pacemaker has a Rest Mode that supposedly enables at night. I have found no documentation to suggest how it determines the time. Or is it enabled based on activity sensing? IDK.

In the spring I traveled to a destination nine time zones away from home, leaving my bedside monitor behind. I didn't track my resting heart rate and never noticed what my heart's rest rate was doing. For the most part it's little enough difference that it is not consciously detectable.

I'm guessing that date and time settings are reset during my every-three-month interrogations, whether in-office or remote. And there is a possibility of resynchronization if you have a bedside monitor that reports nightly. But that’s not going to help if you travel without it. Without the bedside monitor or other connected device, there’s virtually no chance the PM knows of time zone changes.

Regardless, I suspect that your sleep mode is "broken" while you travel, but you generally won't notice. In my experience, my heart only calms to the level where sleep/rest mode is effective a small portion of the time (in my sleep). And if I'm held at 60 BPM instead of allowed to drop to 50 BPM, I'm not going to notice in my sleep. If it were time-shifted to the day I still wouldn't notice because I likely wouldn't calm to the rest level during the day anyway.

A disclaimer - these comments apply for me with a more-or-less properly functioning sinus node. If you have sick sinus syndrome or chronotropic incompetence, your experience may be different.

Global movements and TZ changes

by crustyg - 2024-09-30 11:45:45

There's a philosophical question involved here, too, which isn't entirely academic.

Where a lot of systems are monitored across multiple TZs, it's common to find that the monitoring systems all use the same TZ, which simplifies comparisons of data sources.  For example, something important breaks around 02:13:53 (for the monitoring team) and there are logs which might be relevant for a system located on the other side of the world.  Do you expect everyone to remember that India has a half-hour offset from the TZ/latitude and so miss that the events did in fact happen within seconds of each other, or just have a single TZ for all tools 'owned' by that team - so 02:13:53 is the time to look for in all logs, regardless of where they are located.

In commercial aviation take-off and landing times are always given in Local time, wherever that is - and you just have to know about the myriad of TZs with half-hour differences (e.g. in Canada).  *But* planners talk about Zulu-time - UTC - which is the same around the world and in space.  Think about it - now is the same time here as it is 12000miles away - we just give it a different local number.

My PM doesn't print the currently configured TZ on my reports, but I know that it's set for the UK (not actually sure if it's GMT or Europe/London, as the EP-techs check from time to time at in-person sessions, and I suspect that any time drift is automatically adjusted when a programmer is connected).  If I were to move countries for a long time I would ask for a TZ change.  Otherwise I don't think it's really worth it for me.  BostonSci do their auto-calibration every 21hr to avoid the patient feeling it at the same time every day/night, and this also copes well with TZ changes.  8 auto-cal runs per week.

Auto programming rate response

by Selwyn - 2024-09-30 14:20:46

Some pacemakers auto programme themselves for rate response to exercise  depending on physical activity. This auto programming can occur at less than 24 hour periods.

Crossing time zones, you should find your PM eventually sorts itself out according to your physical activity.

Over the years I have travelled to a 12 hour difference in time zone and have never had a problem with my pacemaker, although it does take a few days to adjust to 'jet lag' - more to do with sleep than the pacemaker.

The auto programming feature nneds to be switched on .