On one recording, report shows svt and rad. on another occasion, ecg showed only svt without rad. is it possible? and what is rad?

Axis deviation: Rad indicates "right axis deviation". Svt indicates "supraventricular tachycardia". Without seeing the tracings one cannot check the accuracy of the interpretations. I would be happy to review these.

Possible: Rad most likely refers to right axis deviation. It relates to the direction of electric current in the heart. Of the things you mentioned, i would pay far more attention to the svt. You need to see a cardiac electrophysiologist.