AF Association
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Erratic HR with Polar HRM


I'm 4 weeks post successful flutter ablation.

Resting HR via old fashioned two finger wrist check and also using Kardia app report a normal sinus rhythm with a rate of average of approx 58 bpm.

However using my Polar M400 HRM coupled with a H7 chest strap the readings rarely seem to match even at rest. When exercising i cannot really rely on what the monitor is reporting.

I have changed the battery in the chest strap. I have used a monitor for a number of years, so know about how it needs to be attached and moistened.

The thing is these odd reports only seem have occurred since the flutter ablation. I wonder how the chest strap measures the pulse. I know that Polar state that incorrect readings may be seen in some people with arrhythmias, but i was getting good readings before my flutter ablation.

Has anyone else experienced similar? I wonder if a different monitor may provide cleaner results ie optical wrist measurement found in the Apple watch as an example

3 Replies

Yes my polar chest strap doesn’t seem to register the ectopic/PVCs so it can fluctuate a lot. I also get more PVCs when warming up. When I had a normal heart beat it worked well and when in fast AF it recorded my 200+ rate accurately but not any more I’m afraid. So it is difficult to measure heart rate whilst moving nowadays. Just reporting my experience not that it helps you with a solution I’m afraid.


Thanks Jo. I wondered if it was somehow measuring the electrical activity that is going on, rather than the actual pulse. My understanding of my flutter ablation is that the activity is still there but the ablation has prevented that activity from causing the irregular heart beat.


UPDATE: After all my concerns whether my heart was performing as it should during exercise, it turns out that the problem was with HR strap giving out false readings.

The straps apparently only have a finite lifespan which this particular one must have started breaking down just around the time of my ablation.

I have bought a new strap and at the same time upgraded the monitor (that clicks onto the strap) to the latest version and all of the readings are now as expected or perceived.


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