Rate response settings too low?

Does the rate response setting of a dual lead pacemaker affect sporting? My PM rate response is set between 60 and 140 bpm. When I am cycling I have the feeling that 140 bpm is too low. It is not my maximum heartrate because I am not running out of breathe at that rate. At least 150 bpm should be better but I don't know if that upper setting of RR at 140 bpm is limiting my max heart rate during cycling. Is there anyone who could explain the effect of rate response and sporting to me?

7 Comments

As far as I know

by IAN MC - 2014-10-20 05:10:17

your model of PM has an " Omnisense Accelerometer" which is fairly sophisticated but is still totally dependant on upper body motion.

We have a resident expert on Rate response ;Inga, alias Golden Snitch who will definitely know whether this is the case or not.

You are obviously Chronotropically Incompetent but there are varying degrees of this , and the extent of your Chronotropic Incompetence can determine your RR optimum settings

Ian

Rare response and cycling

by Tracey_E - 2014-10-20 05:10:48

There are two types of rate response. What type of pm do you have? Most of them sense movement, which means cycling is tricky because your torso isn't moving so the pm doesn't pick it up and raise your rate. Some of them also sense breathing and will use that to raise your rate. So, changing the settings may or may not help, it depends on which one you have.

and ...

by IAN MC - 2014-10-20 05:10:54

to follow up on the points which Tracey makes, are you sure that you are hitting 140 when you cycle ? If your PM is a Medtronic for example it will only have an accelerometer sensor i.e only upper body movement will increase your heart rate.

It is possible that you are not reaching your maximum RR sensor rate of 140 an a bike and that is easy enough for you to check.

The answer to your question in your first line is an emphatic " Yes " but it is not only the maximum sensing rate which is important.

The state of your sinus node will determine how much assistance you require from the Rate Response function.

If your sinus node does not have much function then your RR will be set to respond to minimal exertion.

At the other end of the scale it can be set to respond only to vigorous body movements and exertion

If you think your settings could be better, persuade your drs to alter them while you are on a treadmill but, at the end of the day, rate response is only as good as the sensor in your particular pacemaker

Best of luck

Ian

rate response settings.

by cookenzopy - 2014-10-20 05:10:59

I have a St. Jude Medical Type: Assurity DR PM2260. Symp. B1 ECG: C4 Actiology: B1
I am a 65 years old male and it is my second PM.

St. Jude information on rate responsive

by parmeterr - 2014-10-20 07:10:04

St. Jude Medical (Identity, Vitality, Zephyr, Accent)
These activity devices use an Omnisense accelerometer bonded to the circuit board and are sensitive to accelerations that occur in the AP axis. Activity counts above a programmable threshold (1 = most sensitive; 7 = least sensitive) are integrated and translated to a rate response using a rate-response slope (1 = least sensitive; 16 = most sensitive) (Fig. 5-6).

FIGURE 5-6 Rate-response and “Auto” slopes. A, Rate-response curves from St. Jude Medical activity sensors. B, Automatic threshold (Auto) slope ensures that about 1% of the pacing rate will reach more than 23% of the heart rate reserve (HRR) over time. Note that the sensor-driven upper rate limit (SURL) may not be reached at a low slope setting. LRL, Lower rate limit.
The threshold level can be adjusted manually or automatically (Auto). In the Auto setting, the device measures the sensor activity level over the preceding 18 hours to determine the threshold parameter. The Auto threshold can be adjusted using “Auto threshold offset.” Similarly, the slope of response can be calibrated manually or automatically. In the slope Auto adjustment, the device records the activity variance occurring above the threshold over the last 7 days, and the slope is adjusted to achieve a rate response such that almost 1% heart rate occurs beyond 23% of heart rate reserve. Typically, the slope adjusts by a factor of 2 each week. If the patient has been immobile for the previous week, as indicated by the small activity variance, the slope setting will be held constant, to avoid undue rate response when the patient resumes activity. In addition, rapid manual adjustment of the slope can be achieved by instructing the patient to perform an exercise at a prescribed slope. The Prediction Model will attempt to suggest an alternative slope based on the detected rate response. In addition, the onset and recovery kinetics are separately programmable. These devices also feature a “rest rate” that may be programmed below the LRL. The rest rate is attained when the acceleration sensor does not register significant counts (the “activity variance” level) over an extended period, implying the patient is resting or asleep.

go to: https://www.inkling.com/read/ellenbogen-cardiac-defibrillation-resynchronization-4th/chapter-5/sensors-for-rate-adaptive-pacing

Look at the diagrams.

I am very knowledgeable on Medtronic rate response. They use a three phase graph with a lower rate, upper rate, ADL along with a few other settings. This appears to be a straight line graph.

Hope this helps.

Richard

RR when cycling

by golden_snitch - 2014-10-21 03:10:50

Hi!

First of all I'd like to ask what your condition is: sick sinus syndrome, heart block, both?

I just read that you have had a Sorin Reply pacemaker, and now you have a St. Jude and are reporting problems when exercising. The issue could be that your Sorin pacemaker had a dual-sensor rate response with a motion sensor and a minute ventilation sensor; your St. Jude has the motion sensor only, and that has its limitations when it comes to activities without any upper body movement, like cycling. The others have already explained this to you. The Sorin pacemaker did not have these problems, because it had the minute ventilation sensor in addition to the motion sensor. A minute ventilation sensor does not need upper body movement to sense activity, you only need to breath faster or take deeper breaths.

So, now with the motion sensor only, I'd be surprised, if you do reach your upper programmed rate of 140 when cycling, and this rate is indeed sensor-driven. If you feel that 140 is not enough, let them increase the upper limit.

The upper programmed rate can only limit your heart rate when you a) have a very slow sinus node with chronotopic incompetence, or b) when you have a heart block. In patients whose sinus node is functioning well when exercising and who do not have a heart block, the sinus node could easily exceed the upper programmed rate. In this case, the pacemaker would just watch. In patients with a heart block, but a healthy sinus node, what matters most is the upper tracking rate. If the pacemaker is set to track only up to 140, their sinus node could do for instance 200, but the ventricular pacemaker lead would not pace the ventricles at the same rate, but only up to 140.

Best wishes

Inga

Thanks for your comments.

by cookenzopy - 2014-10-21 09:10:55

I live in Europe, so there is a time gap between US and Europe. I am sorry for the late response but I thank you all for your comments. In 2007 I got a pacemaker because I have had a second degree heartblock. At the end of 2009 I also got AFIB. This was getting worse and worse and resulted in a Sick sinus syndrome and also chronotropic incompetence. I used beta blockers to contol the SSS. My max heartrate was due to the beta blockers 95 BPM. Walking upstairs made me completely out of breath. I felt myself as a walking zombie.
In November 2013 I had an ablation and it was a great sucess. I am free of AFIB and I have an own sinus rithm again. However it is too slow (30 BPM). So my PM is still regulating my sinus rithm at 60 BPM. Because I don't use beta blockers anymore cycling is great fun again. I have only doubts about rate response settings and my max heartrate. I shall talk with my PM technician about this issue in January because it is rather difficult for me to understand what RR does and what not.
But your answers were very helpful and thanks for that.
Best wishes,
Hans.

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