INCREASE IN MODE SWITCHES

Latest report shows 1,340 Mode Switches over a 6 month period.
Adapta Medtronic duel lead with rate response off. The detection rate was lowered to 160 from 175 before currant report. There were 40 Atrial high rate episodes and 5 ventricular.
Any thoughts will be appreciated.....-Philman

6 Comments

Mode switches

by golden_snitch - 2014-06-18 04:06:27

Hi!

Which mode switches are meant? The ones occuring when you go into atrial fibrillation or the ones that happen when you have heart blocks? Your pacemaker can do both. It can switch modes for instance from DDD pacing to VVI pacing when atrial fibrillation occurs, but it can also switch from AAI to DDD when you have intermittent heart blocks (that's what MVP feature is for).

If these are the mode switches for atrial fibrillation, I do not understand how you can have 1,340 when you had only 40 atrial high rate episodes. Or does your device not include atrial fibrillation in the atrial high rate episodes, but counts them extra? Also, with the detection rate set that low, anything above 160 will be counted as a high rate episode, even when you were just exercising and that brought your heart rate up. Doesn't make much sense, in my opinion.

Inga

Mode Switches

by Philman - 2014-06-18 11:06:53

Hi Inga, Thanks for the comments. I did an analysis of the last ten reports and the increase in Mode Switches was for the last two. The preceding report indicated 1,055 but was for a 18 month period. Before that there was a range of 2 to 9 a mo. The Post Mode Switch Pacing was turned off prior to the mentioned reports. I have been active with tennis, running,swimming, and most recently, boxing.

I have normal AV Conduction, and have a DX of SND. Also had two Ablations at the Cleveland Clinic. Would one feel the Mode Switch as it happens? Should I be concerned?

Thanks , -Philman

ok

by boxxed - 2014-06-19 10:06:22

Medtronic doesn't really count how often it switches from AAI -> DDD. % of V-pacing is used as the way to measure that. So it's saying 1,340 switches to DDI.

The reason why the discrepancy between 1,340 Mode Switches and 40 AHR's, is that they use different criteria to become one or the other (or be double counted as both). I'd have to look at a parameters printout to remember what nominal AHR criteria is. For Medtronic, Mode Switch isn't considered an episode. AHR is. This is unlike St. Jude, which considers a mode switch an episode as AMS.

Should you be concerned? Probably not. But you'd have to ask your doctor, honestly. They switched the detection rate (of VHR I am assuming) from 175 to 160. Why? What are they fishing for? Are they suspecting arrhythmias that weren't recorded? On paper, 40 AHR and 5 VHR doesn't sound bad if you have known AT/AF. It depends how nasty (or long) the actual EGM's looked.

hrmm

by boxxed - 2014-06-20 01:06:26

Consider talking to your doctor about it and voice your concerns. It sounds like you don't feel comfortable with these changes, and by extension your technician. If it were me I wouldn't like uni-lateral changes being made on me that were more than the simple parameters.

AV Delay settings should be in the middle bracket of the first page. Nominal settings are in the 200-230 range. If you find youself in the 250-350 millisecond range, they're extending the AV Delay purposefully to avoid unneccesary V-Pacing. There are two types of AV Delay, PAV and SAV. Both are how long the pacemaker is willing to wait depending on whether the P-Wave is naturally from the heart, or if the P-Wave was artificially created through the pacemaker.

If I recall correctly, PAV should always be about 20-50ms longer than SAV, because Sensed P-Wave takes advantage of the natural conduction circuit, while Paced P-wave is a bit unnatural in how the signal spreads and goes cell to cell throughout the myocardium.

Sorry I can't be more help aside from throwing definitions at you.

Good information

by Philman - 2014-06-20 10:06:11

In the last two reports with the 1,000 plus Mode Switches the Paced AV was changed from 180ms to 200ms and the Sensed AV was changed from 150ms to 180ms. That may be good as the V pacing has dropped to 2.6% from 4.1%. It still puzzles me that in the last 10 reports before changes, very few Mode Switches and V pacing always under 1.0%..

Scheduled visit to the Cleveland Clinic in July where I plan to have a stress test in conjunction with optimizing my settings. Had an incident two weeks ago playing tennis and I felt a high heart rate and then the "ground was coming up".... sat down and lowered my head but close to fainting. Report says Atrial High Rate for 5 minutes followed by Ventricular High Rate for 6 minutes. Just wondered if I exceeded my upper upper Tracking or Sensing rate of 150, followed by a quick drop. My H/R was 60 and B/P normal within minutes.
Are there any settings to prevent this?

OK no more Questions I promise....-Philman

I understand but

by Philman - 2014-06-20 12:06:23

My tech does not appear to be making changes per the Doc. She does not want me to see the interrogation rpt. much less the changes made. She put on Rate Response with oversensitive settings and I had 1097 mode switches in 9 days and went back with PMT. this created the start of persistent A-Fib and my 2nd Ablation at the Cleveland Clinic 3 years ago. Recently she has turned off post mode switch pacing, lowered my detection rate, and made my leads much more sensitive then they were. sensing assurance was turned off also in the Atrium. I think she and Medtronic feel I should be on Beta blockers with the R/R on. Been free of A-fib for over three years and do not take any medication. Im not sure why but I was told I would never get my Heart Rate over 60 without the R/R on. I am very active without it with tennis boxing, swimming and working out. However, I think there are some tweaks that can be made to get my energy back when I am not exercising...Does the AV Delay setting help with this? And where is that information on my report?

Thanks boxed, you have a real grip on the education and information of Pacing..

-Philman

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