My HR does not rise when I run

I am a 69 year old triathlete and having a PM implanted this week. I have a low resting heart rate, about 42. I have been experiencing dizziness and shortness of breath when running. On a recent stress EKG, my HR did not rise above 74 when I was running on the treadmill. When not exercising, I sometimes have mild symptoms, but am generally OK.

I understand that a PM will pace the heart of a sedentary person to a higher HR if it falls below a set level and bring it back to a certain minimum.

My question: Can a PM sense that running is putting an increased demand on my heart and pace it to a higher HR, perhaps 125 or 130?

Thanks

6 Comments

Yes it does

by Theknotguy - 2015-08-03 08:08:22

Ian is correct.

They had me on a treadmill during my cardiac rehab. While I wasn't running, I could watch my heart rate on both the treadmill and the heart monitor as I was doing a fast walk. You could see both numbers increase as I started walking faster.

My PM, a Medtronic, has an accelerometer which is supposed to increase your heartrate while exercising. Because I was almost stationary on the treadmill, I had problems with the chronotropic incompetence Ian discusses. However, as I was able to increase my speed, the PM would increase my heartrate to match. It was a good learning experience because I was able to see how quickly/slowly the PM would react to that type of exercise. I was able to learn to compensate.

While doing actual walking, the accelerometer reacts much more quickly than it did on the treadmill.

You may want to fill out your bio if you have any more questions. Knowing the type of PM you have can make a difference as to how we answer some questions.

I hope everything goes well for you.

It certainly can !

by IAN MC - 2015-08-03 08:08:51

It sounds as though you are " chronotropically incompetent " which means that your heart rate doesn't increase as it should when you exercise . You probably have a lazy sinus node !

To help overcome this, pacemakers have a function known as " Rate Response " which basically consists of an inbuilt sensor which detects when you are exercising and then tells the pacemaker to generate more heart beats.

With your inability to get your HR above 74 it is essential that you have Rate Response switched on !

The success of this function totally depends on how good the sensor is and how physiological a response it generates.

I hope that your doctors take into account the fact that you are a triathlete before choosing the best pacemaker for you because there are different types of sensor.

The commonest one is known as an " accelerometer " and simply detects movement in the upper body which is OK for running but not so good for cycling.

Some PMs have a built-in second sensor which detects increased breathing and this, in combination with the accelerometer sensor, is probably the best choice for
triathletes such as yourself. This is known as a " minute ventilation " sensor'

Once you have Rate Response switched on, you may need further sensitivity adjustments to the PM to ensure that the rise in heart rate matches the sort of exercise you do.

Best of luck

Ian

Same boat

by Jackw - 2015-08-04 01:08:33

I have virtually the same profile (age 69) and problem (sick sinus, chrono incomp). Just not a triathlete. I run hike and ski. Looked into PMs for me and decided on a Biotronik. It has a system called CLS which measures the stress being put on the heart and revs up as needed. Before the PM I could not get my rate over 85-90 and ran out of gas. I am now getting my rate up to 125 plus on a tread mill or out on the road and feel good after. The other feature to consider at our age is MRI compatibility. Mine is MRI compat.

Rate response

by golden_snitch - 2015-08-04 05:08:48

As the others already pointed out, it's very important for you to discuss rate response sensors with your cardio. Medtronic and St. Jude pacemakers all feature an accelerometer (motion sensor) only, which comes with a few limitations with regards to swimming and biking and any activity that does not include upper body movement. So, these manufacturers are not the perfect choice for you. Sorin Group and Boston Scientific offer the minute ventilation sensor + accelerometer combination, and Biotronik has the CLS sensor, which is based on measuring cardiac contractility.

I have tried all sensor options, and based on my experiences I'd probably recommend the minute ventilation + accelerometer combination rather than the CLS. I have a CLS sensor now. It works well during daily life activities, but I do have some problems when I run and I also hate that CLS resets itself whenever you change a setting (which then causes three days with lots of inappropriate tachycardia). Also, keep in mind that CLS has an upper rate limit of only 160bpm, while other sensors can easily pace you up to 180-220.

All the best!

Ultrapacer

by ultrapacer - 2015-09-01 03:09:11

Go get help. I run and bike and it took many attempts to get my pm set properly. If your heart rate won't go over 74 it's not set right. Don't be shy. Keep going back until they get it right b

Ultrapacer

by ultrapacer - 2015-09-01 03:09:59

Go get help. I run and bike and it took many attempts to get my pm set properly. If your heart rate won't go over 74 it's not set right. Don't be shy. Keep going back until they get it right b

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