Help me understand pacing percentages
Ths is an interesting word problem, so please give me time to set it up.
I recently went to my electrophysiclogist (EP) because I continue to have ventricular tachycardias, sometimes three a day. Luckily my ICD paces me out before it delivers the horse kick. They looked at my intrinsic heart rate and decided the low rate of my PM was too high, so they knocked it down from 60bpm to 45. They also dialed down my atrial tracking. My intrinsic resting rate wants to be 48-50. after this change, I never felt better. I had the best nights sleep. It didnt' solve the VT problem. But that's not what this post is about.
On a subsequent visit after it was clear it didn't solve the VT problem, I was anxious to see how much I paced in the upper chamber since they knocked the low rate down to 45bpm. They told me 30%. I was shocked. I had been at 75-80% before the change and that was because the 60 setting never let my intrinsic resting rate take over. With the new setting, I was expecting 0% pacing. I know my heart rate. We all do if we have pacemakers, right!? I have never broken the 40-bpm yard line. And if I do during sleep, there is no way it could reach 30% of the time because even on my best nights sleep I sleep 6 hours. And 30% of a 24 hour day is 7 hours and change. I questioned my EP.
Well, if i crossed the 45 bpm threshold and was paced, at what rate would my intrinsic HR have taken me if I didn't have the pacer. He said it looks like in the 30s. That's impossible, I told him. Absolutely impossible because I never feel dizzy unless I experiene a VT. I'm as strong as a 16 year old (58 now). Also, I'm testing my pulse all the time in all situations. I track the pulse rate and then I track how quickly it goes back to resting after exercise. Furthermore, I am counting and recording any erratic rates (very few).
How can my HR be in the 30s or at least below 45 bpm 30 percent of the day and me not know it? I don't even sleep 30% of the day. And that's when he said something I had never heard.
He said the 30 percent is not a percent on the whole day but rather moments during the day. Don't know how to process that but Ok. Good to know. But I NEVER reach the 30bpm either, how do you explain that. He would point to the computer and say it says here.
Here is what is happening, I think.
When I was in hospital's telemetry ward being monitored for a possible PM. My finger never left my pulse and my eyes never left the heart rate monitor. I wanted to know every move my heart made. During calm times my pulse would be at 60 bpm suddenly it would jump down to 30 bpm. That corresponded with a skipped beat that I felt on my wrist. But the pulse went back to 60. The computer recorded a HR of 30bpm, if only momentarily. It didn't raise concerns among nurses on telemetry because they all know hearts skip beats and these computers also show whether it was sustained. In my case it was not.
Fast forward to a tech in a doctors office with a machine. He may or may not have medical experience. But today he represents a company that manufactures pacemakers. He is trained not to give medical advice. But he does give information if asked. How low did my HR go, I ask. He says, it went into the 30 bpm range. I know that was wrong. My EP said the same thing.
We with pacemakers know our hearts better than even the doctors. Today I am getting a watch that will record my every beat and provide accessible, historical data.
Does anyone have any light to shed on how measurments are communicated. And don't tell me to get over it. I won't. LOL. All the best to everyone.