HeartChart

Bluetooth Low Energy Heart Rate and Variability application.

The author of this application suffers from atrial fibrillation and wrote this app to monitor both his heart rate and the heart rate variability, the RR value, as read by several “Bluetooth Smart” or Bluetooth 4.0 Low Energy devices.

The RR value is the time between beats and is generally a more accurate reflection of heart arrhythmias (irregularities) than the simple heart rate reported. Note that minor variations in RR are generally considered to be a good thing and you can watch, for example, minor RR value changes as you breathe in and out. However, wider variations could indicate an AFib or other heart arrhythmia event and require full evaluation by a medical professional using medical grade diagnostic equipment.

IMPORTANT: This is NOT a medical application and the user should NOT base any medical decisions on the output of this application; however, it is interesting and informative to see both the rate of the heart and the variability of that rate; especially for someone who suffers from chronic heart arrhythmias.

The application will display the highs and lows of both heart rate and RR since the most recent connection. It will also show the average and standard deviation for RR and Heart Rate for the most recent 1 minute.

This has been tested with the “JARV Run BT Premium Bluetooth 4.0 Smart heart rate monitor”; and the “Zephyr HxM Smart Heart Rate Monitor”. However, this should work for any Bluetooth Smart heart rate monitors supported by Android and that support the RR interval.

INSTRUCTIONS:
Wet the collection patches on your Heart Rate Monitor ("HRM") strap (I use warm water and wet the plastic collectors on the strap and the skin under them). TIP: others report longer term success using EKG gel.

The app looks for a HRM on startup; but you can press SCAN if you attach after startup to find a new strap.

Press Connect. You should immediately see the Heart Rate and the RR, and the minimum and maximum readings are also reported.

Important: The Min/Max readings are reset when you connect. Therefore, if you want to reset them and the minute timer after reporting has already started; simply press the "Disconnect" button on the Action Bar and then "Connect" again to reset everything.

The Average values are reported each 1 minute the application has been running..

One final point: the RR and the HR are inversely related. That is, when the heart rate is up, the RR will be down and vice versa.

I have seen extra beats recorded by seeing a low "Minimum RR" that is much below the average. I have seen missed beats recorded by seeing a long RR that is much above the average. Again, this is NOT a medical device and do not base health or medical decisions on this 'free" application.