Hello and hope you are doing well.
If you have a small VSD with no additional problems and if you're cardiac function is normal, you can engage in all athletic activities. However, if you have additional problems, such as shunting, rhythm problems and valve problems, you should consult with your cardiologists about what kind of exercise is most appropriate for you.
Hope this helped and do keep us posted.
As long as you don't stain yourself too much
And what about just doing dips and sit-ups and stomachs exercise without any instrument or heavy weight.
With a VSD your exercise tolerance will be diminished, however there's no reason to exercise. I suggest jogging or walking, it decreases arthritis risk and strengthens the heart.