How to measure the heat rate accurately

[EngMac]

This topic was posted a day ago and I made a comment about which some of you could be interested and may miss because the post was a day ago. So I have posted its again here.

I have a three lead EKG device that shows the heart rate. What it shows is a very irregular chart, when my heart is in AF, and, when I have shown the chart to the ER staff and my cardiologist, they seem to think the representation is accurate. I suspect the rate is erratic since the heart is adding and missing beats in a random fashion. This is a layman's guess. My cardiologist told me that he can tell the heart is in AF since the "p" part of of each graphical representation of each beat is missing.

EKG devices are available on the internet. Each has a different number of leads. The one I have was specifically designed for a cardiologist to monitor his patient's AF and other arrhythmias so I suspect it shows a chart somewhat close to reality. This cardiologist gave me feedback on my charts. Unfortunately, the designers of the device, his sons, no longer sell it to the public. Purchasing an EKG device is likely the best way to get a picture of what the heart is really doing.

Kardia, being a one lead device, I believe uses an algorithm to generate the chart. DrDave01,who posts on this forum, can likely explain how it really works and if it accurately depicts all the heart iterations when it is in AF.

I doubt that you can manually count the pulse accurately when the heart is in AF. I also doubt if heart monitors on the chest can either. By feeling the pulse, and when it is very erratic, you can tell the heart is beating irregularly; and, for me, when I record a chart, the heart is always in AF. So all I have to do is feel my pulse to know when my heart is in AF and when it is not. Too bad doctors would not tell us what the feeling is. But, then they do not have AF and maybe have not felt the pulse when it is in AF.

By looking at hundreds of my charts, I have noticed that when my pulse misses a beat, it is often an extra beat, which I cannot count by feeling my pulse. So my heart has not missed a beat, but instead added one. For this reason, I conclude that when the heart is in AF and quickly adding and missing beats, these cannot be manually counted or likely accurately counted by a typical heart monitoring device like a blood pressure cuff. If the AF is somewhat regular, perhaps the rate can be counted accurately; but my AF is never regular so I cannot when I have tried, while I watched the chart being recorded.

When in full blown AF, the heart rate is likely changing so quickly, probably only a hospital grade EKG device can see all the changes. For most of us, we just want to know if our heart is in AF or not. For a more accurate indication, we need to have a professional take a look. But most times, this is not necessary.

I am not on heart medication now; and when I was, I did not have enough experience using the EKG device and I did not have enough AF episode experience to "hazard" a general guess as to what was happening with my heart; so, therefore, I do not know how heart medication changes what the heart does and what the charts would look like as a result. From what I can remember, the charts did not look materially different when my heart was in AF.

I hope this has helped.

[Mercurius]

Hi EngMac,

I also use my private one channel ecg for monitoring my afib. Being MD. I also understand what I see. Concerning your questions:

1. We can measure only the average of our heart rate. I takes usually 30-60 secs. In normal case if your repeat the measurements, you will get same value. But in arrhytmias it is not the case. That's why with autamatic blood pressure measuring devices usually stop with error message in arrhythmias. Anyhow ECG will give some sort of heart rate values in afib. The repeated measurements will give different values, but all of them will be elavated. That is the TACHICARDY, THE FIRST HALMARK OF THE AFIB.

2. The SECOND HALMARK OF THE AFIB is the ARRHYTHMIA - uneven distribution of the R wave along the ECG curve.

3. THE THIRD HALMARK OF THE AFIB is the MISSING P WAVE.

4. THE FOURTH HALMARK OF THE AFIB is the "trembling" basline (good quality, low noise device is needed for find it.

Unfortunatly sometimes the tachicardy is so so high, that the 3-4 points could not be demonstrated. Then medication is needed to slow down the heart.

Conserning the pulse rate we have to keep in mind, that in arrhythmias not every contraction is resulting effective blood pumping, therefore the pulse rate might be slower the the heart rate.

Best regards:

Mercurius

[UScore]

Will the Kardia show that the p-wave is missing?

[EngMac in reply to UScore]

Thanks Mercurius. The device I use has three leads so it gives a bit more information than a one lead device I assume. So from what you have told us, even the sophisticated ECG machine in the hospital has its limitations for showing definitive results. Yet, perhaps significantly better than blood pressure monitors, pulse recording devices, etc. Good to know that there is still some measure of judgement needed by the doctors and this may be why different doctors give a slightly different diagnosis.

I have a left bundle block and I have been told that this electrical problem makes it even harder to accurately diagnose AF when using the ECG. I was also told that it lengthens the QRT interval as does some AF heart medication and therefore the cumulative effect can be negative on overall heart function. Maybe even negative for the last time. Something to question the doctor about when a heart medication is prescribed, partly to insure that they have taken this into account.

[momist]

Just to clarify what may be confusing to others: The Kardia has two contacts on it, to record a single channel of the heart's electrical signature between the arms, and therefore across the heart. A three lead EKG machine would therefore have four leads, requiring contacts to be made in specific areas of the body, normally arms, chest, left leg. This gives readings of the heart's electrical signature in three direction across the heart, the fourth connection giving a reference point. All readings may be subject to interference from other electrical activity in the body, and will normally be filtered by software algorithms to produce a trace.

No, I'm not a doctor, but this is my understanding from what I have read on the subject.

[fluttered]

The Kardia does show the P wave during normal sinus rhythm. During Afib or Aflutter when the heart is beating fast, the P wave can be hidden by the QRS wave. The rhythm must be slowed to see or not see the P wave. I have a 10 lead monitor. I would have to find a time on the recording when the rate would intermittently slow in order to see no P wave or the flutter wave.

[Hidden]

Hi EM

From a patient perspective, a stethoscope and watch is probably the level of sophistication necessary to measure heart rate in atrial fibrillation. A pinpoint accurate reading is surely never necessary?

Or have I missed your point?