What to do when in SVT (supraventricular tachycardia)?

I have had several episodes of SVT, the last of which landed me in the hospital for several days and a change of medication to diltiazim (along with my many others). I will be reviewed by an EP in a few months (!) and probably discuss having an ablation. I have a very complicated heart history - open heart surgery to repair mitral valve, episodes of Afib, cardioversions, an ablation, etc., but overall am in very good health. My heart and I get along pretty well! This SVT is annoying, however. When I'm in an episode, I try vagal maneuvers, which has worked a couple of times. Otherwise, I have to head to the hospital with my heart rate thundering at 160 - 190. I'm not really frightened by all this, probably because I"ve been through so much; however, the fear of SVT is ever present. This causes me to restrict airplane travel and activities which would involve not being close to a hospital. I mean, what do I do at 35,000 feet when I can't get my heart rate down and I'm 4 hours ( 8 hours on an oversees flight) away from land? If you have had any experience with SVT, I would welcome your experience and suggestions. I hope this finds you all well! Thank you, Sue