Since starting steroids for GCA I've had erratic heartbeat and also tachycardia which was lasting about 10 and then resolving, generally after doing things like handling my horses. Yesterday I was exercising one of the horses on the lunge, which involved a lots of walking while he circles round me in walk and trot on the end of a 20 metre line. The tachycardia started, but just kept going. I managed to get him finished and back out into his field, and then (foolishly I know) drove myself home. By this time it had been going for about half an hour. My husband took over, and called an ambulance. Paramedics hooked me up to an ecg machine and confirmed I was having an attack of supra ventricular tachycardia. It actually stopped while I was in the ambulance, but had lasted about an hours by then, leaving me feeling weak and as if someone had punched me in te middle of my chest. I spent the next 10 hours wired up to an ECG machine having various blood tests and then spent the night there being discharged This morning with a prescription for beta blocker to add to my pill collection. I'm now waiting for and appointment with cardiology for an echocardiogram and a 24 hour ECG monitor. Frightening, but at last I feel that my heart problems are be properly investigated, rather thN being fobbed off with being told that I should expect to have rapid heart beat on steroids. My point has always been than heart rate should not be fluctuating between 70 and 140 randomly and rapidly throughout the day! Finally this has happened in front of a doctor while I was connected to a monitor. I'm now back home, and feeling better after the beta blocker.