Few here, I think, would recommend against your existing medical advice. Your doctors have the best data and knowledge/experience to advise you.
I follow my doctor's recommendations. I am one year older than you, so I do not stand a a proof of living into 80 years, but I can say I have suffered from atrial fibrillation and other heart problems for about 15 years and following my medical advice has helped sustain my life that long.
I'm wondering if you mixed up terns? I know of non-sustained ventricular tachycardia which is NSVT. I've never heard of Non-sustained Supra Ventricular Tachycardia though. These terms can get confusing but they are very different.
NSVT in a structurally normal heart is usually labeled benign.
Like Jerry says follow your doc's orders.