I have had svt and inappropriate sinus tachy for 19 years ablation unsuccesful. I take 50 mg of tenormin. It controls the svt well but I get alot of palpitations. I notice that when I am outdoors at night even at a pleasant temperature, my heart beats irregular and is quite uncomfortable. My ablation was unsuccesful due to the problem being by the phrenic nerve and they were worried about it seizing up. I feel like this condition impairs me greatly. What can I do and what is with the night time air?

Thanks so much