Ok everyone can switch off here, I'm going to get a little bit technical: SVT is a form of junctional tachycardia which means the stimulus for the heart beat originates from the AV node of the heart rather than the SA node, which usually "fires" to stimulate the normal cycle of heart activity (ie, a beat) In the example above, the tachycardia is regular, but as you deduced Bsteph, the heart is going through it's cycle much too fast to have effective filling and emptying of the atria and ventricles, hence a decreased cardiac output (bloodflow) that compromises the patient. Irregular heartbeats are another thing. It sounds like they performed a "stress test" with your mother, which is quite a common test and often picks up any potential problems early on. There are a multitude of drugs to deal with irregular heart beats! I hope your Mum is feeling ok now. BTW, I sometimes feel like I'm going to "have a cow" but I hope I don't outwardly show it...it tends to scare your patients!! lol I thank you all for your indulgence in this non-photographic topic. My job isn't that terrible, sure it has it's scary moments, but it is always scarier for the person in the bed! Also, I asked for this job, and have been doing it for over 20 years now...so I really can't complain! It's more rewarding than draining, most of the time. I started this thread more to share with you the (belated) revelation I had as to how truly bizzare some of the things I do must seem to others! The doctors get heaps of responsibility on their shoulders, I'm glad I'm a nurse! (Also I think of Air Traffic controllers and the like, now that would be stress)...Right! Enough of this! - back to photography! Thanks everyone!!!