We have our own machine, and last summer, when cutting down a huge hedge and had hay fever at the same time, I got the reading that I had an irregular heartbeat. Had an appointment with the practice nurse within hours, and then a hospital appointment within 3 hours. They gave me a test thingy where you have sticky pads on your chest, and 2 weeks later decided I had nothing wrong and it was most likely stress and the wrong kind of anti-histamine pills! And all this from a surgery that gets slagged off by some, and a hospital that has been in special measures twice and is again. The interesting thing is, someone told me that a gluten-free diet can help (!!) so I tried it and there was an immediate effect. I have gradually come off it, and touch wood have had no further symptoms.