Been using this Blood Pressure app now for a few days and I really like it.
Amazon product ASIN B00JM6EBHG
I did some research on various devices and while none were perfect, this one seemed to have what I wanted and the least number of complaints by reviewers.
It is not just an iOS system but works with Android smart phones too. But, it is said to work in tandem with Apple's Health monitor sharing data for a single report that can be sent to your doctor's email address. I really like how it tracks the BP data on a chart and monthly calendar as a line graph. Plus, it also displays the data on my Apple watch as well as being able to operate the BP cuff from the watch.
Now for the complaints-
As was reported in the many reviews, the Quardio is a bit finicky with turning it on and pairing with the blue tooth connection. I found the trick to overcome this is when you open the cuff which is supposed to turn it on, it saves time by popping the battery compartment open and close, then launch the app on your phone, then it will connect using BT. Also, there are two settings that are off that need to be turned on so connection is done automatically after first time pairing. Now you can operate it with either your phone or the Apple watch. These additional use instructions were not in the paperwork that came with the unit and why so many complaints on BT connection were in the reviews.
An improvement would be to just be able to open the cuff and slide it on your arm, then touch your Apple watch and it would take the readings, log them, and be done. Unfortunately, this new version, seems to require starting the app on the phone and doing the battery door open and close to wake it up. Sort of negates the whole point of having the Apple watch being able to operate it. Apple watch convenience? NOT!
But even with the awkward startup, This device makes taking BP readings daily and logging them into a nice report that can be sent to your doctor or just entered into your personal log.
In addition to blood pressure and heart rate tracking, the Quardioarm device checks for atrial fibrillation and if detected will popup a warning and log that as well.
There is a real atrial fibrillation monitor you can get for iOS by another company, but it is very expensive. $595 for the equipment which is a BT connected chest strap with sensors, like a multipoint ECG, and then there is a subscription fee to subscribe to a service that monitors the readings over the internet.