I am very pleased with the Alivecor monitor. It recorded sessions of:
Atrial Fibrillation RVR, Atrial Flutter, PACs, PVCs, V.-Tach/PVCs, and readings up to 214bpm -at which time I had to put it down! Alivecor's email support was very helpful as well.
Check into the user manual, (on the menu: HELP, User Manual)
There are several different ways to take readings and some have greater accuracy than others. The best one for me is Lead II, which is above the left knee combined with the fingers of the right hand. The Lead I which is both hands, gives me some wild readings which really threw me off sometimes. Lead I only records well for me when I am actually in Afib. Lead II nails it everytime regardless. Anterior Precordial Lead works as well though more awkward in public to use (center left on chest, above the breast). One great tip Alivecor gave me: use hand sanitizer (on any fabric that won't be damaged by such) on your knee and it will even read through pants! And it does!
One thing I've have learned, if I have a doubt - then I am NOT in AFib.... when I am sure without a doubt it is clear even without the device. The rest is what the Drs love to belittle..as. your "palpitations". I wonder if in our learned hypervigilance we are not better tuned to our hearts - and one day they will have an apparatus that can actually read what we are feeling!
In any case, I have been grateful to have these recordings to hand over to Doctors. Thank you Dr. Albert.