@bhagya99
First I wish you luck.

I can pass on my experiences with this. In the past I have had a lot of PVCs. I also had episodes of VTAC. This resulted in ICD (I have had a ICD/Pacemaker since 2006) shocks. For a lot of time just could not get under control.

What you experiencing with the hard thump sound like what was explained to me was a adrenaline. This will really give you hear a thump and start beating like crazy. This was confirmed to me (VTAC) as I have my ICD/Pacemaker record tested and confirms the VTAC and leading up to it high pulse rate.

Many things can cause adrenaline rush and/or what you are feeling. Are you under a lot of stress. If you are talk to your doctors about it. There are a lot of medications out there to help with it along with suggestions from your doctors on exercise, hobbies, consuling.

Very new and ongoing good medications are out there to help with heart arrymias (spell) and helping prevent VTAC. I was put on them and really helped me as have not had those feeligs in over a year now.

Good luck!