The functions of my pacemaker
The first is to ensure my heart doesn’t go too slow and currently it is set to prevent my heart from going slower than 50 beats per minute.
ICD’s built-in accelerometer
It also has a function called an accelerometer. This senses the movement of my chest and decides if I need a boost to the speed of my heart to obtain sufficient oxygen for the activity it has sensed. If it thinks I need more oxygen it will deliver minute electric pulses to my heart to speed it up.
The third function is to work as a defibrillator which means that if the speed of my heart goes way out of control or it stops altogether it will deliver a strong electric shock to start a heart again, hopefully with a normal rhythm.
A final thing is that the ICD stores a record of my heartbeats and understands if something unusual is going on. If it senses a problem it will send a message over the mobile phone network to the pacemaker clinic in the Royal Sussex Hospital in Brighton. The clinic can then take any action it thinks is necessary including alerting the cardiac consultant and my doctor. Every night my pacemaker communicates with a transmitter in my bedroom. It’s like having a spy in my chest.
Monitors heart activity and reports automatically by mobile phone network
It was because this facility functioned in June 2019 that the hospital realised the atrial chamber was malfunctioning and that is why I was put on the anticoagulant. So the pacemaker diagnosed the problem and alerted the doctors. Without it I would not have known that I needed further medication.
Is the pacemaker working correctly?
Maybe not. Although I’ve been feeling very well this year my main concern has been that my heart rate sometimes seems to go up very high and for no good reason. The problem occurs if I jog or do any movement which involves my chest going up and down relative to the ground in such exercises as squats or skipping or jogging. In a few seconds my heart rate can go from 70 beats per minute to 130 beats per minute, even though I am not the slightest bit out of breath.
When I went to cardiac rehab classes at the Princess Royal Hospital in Haywards Heath shortly after I had the pacemaker inserted I was advised that a safe heart rate for me to exercise at was between 90 and 105 beats per minute.
My own heart rate monitor
I would never have known about this speeding up of my heart rate if I hadn’t bought a high quality heart monitor, the same brand that they use in the hospital cardiac rehab classes. (Polar)
The follow-up to having my my pacemaker insertion has included visits to a cardiac consultant. I told him that I was puzzled about why my heart was suddenly speeding up so much when it didn’t seem to need to do this. He suggested that he reason it may be speeding up might be because of a device within the pacemaker called an accelerometer. He suggested that when I next had an appointment at the pacemaker clinic in Brighton I should ask them if an adjustment might be made.
In fact I went to the pacemaker clinic on the 4th of November and I will write about this experience in due course.
27 November 2020