Ablation is not for everyone and many arrhythmias are treated fine with medications. For those who do choose ablation the risk of pacemaker is low (<1%) in general. Atrial tachycardia can have a variety of different causes but is often caused by an "ectopic focus" of cells firing at their own rate. Accessory pathways ('extra pathways') are present at birth and persist throughout life unless they are ablated. Arrhythmias can be episodic. They are not usually part of MVP syndrome.
Sorry I don't understand why the name dande4 keeps coming up. It may well be my wife's nickname which I did not know. She is out of town and may well have posted that prior question and her nickname is logged in on my comp. as well. I did not notice until too late. I am very Sorry for using a double post that someone else could use..I will try to research this...
Please don't worry. I have paroxysmal atrial tachycardia along with mitral valve prolapse and microvascular spasms. I also have a very healthy heart (according to my cardiologist) and feel great since my cardiologist found the right meds. An ablation was attempted, but was aborted because it would have meant a pace maker for me which I did not want. I am on Rhythmol (side effects sound scary, but I have experienced none) and the arrythmia is totally under control. All my other heart problems are under control and I feel great. There are meds instead of an ablation. Please speak to your cardiologist -- it makes a work of difference to be on the right meds! Good luck!