At much over 180 beats per minute the heart chambers have a hard time getting enough time to fill with blood - so sure very fast rates can be dangerous no matter their source - atria or ventricle. Fortunately you have an otherwise young, healthy heart and it can withstand running it at full speed without too much apparent trouble; as evidenced by the fact that you have tolerated in the past. You can learn certain techniques to arrest PAT's. I think it would be worth your while to learn them. It may be worthwhile to consider medications as well - though admittedly they are not successful in every person. Regarding the ablation - you certainly seemed to discount that as too scary and too risky to investigate it. An electrophysiologist is a highly trained and capable cardiologist who is a specialist in these matters. It would very much be worth your while to discuss this matter with one of these specialists. He/she could do a procedure that last takes an hour and fixes the problem for life. Very good techniques are available that were not available ten years ago when your rhythms first started. With this type of ablation you will not require a pacemaker. Give it some thought. I hope this helps. Good luck. See the link below: http://www.mayoclinic.com/health/heart-arrhythmias/DS00290/DSECTION=8