Hi,
Welcome to the ehealthforum and I am glad to help you out.
What you are having is worsening of the SVT and for the confirmation of the same we usually do a 24 hour holter (ECG) monitoring and this is picked up in such a monitoring. In case, it’s confirmed, then another study called the electrophysiological study is carried out to look any abnormal electrical pathway in the heart to cause this tachycardia (fast heart rate) and the treatment lies in ablation (damage) of this abnormal pathway.
You may need to get additional medicines prescribed. Hence please consult your cardiologist and get these investigations done.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.