What Causes Occasional And Sudden Chest Pain In A Tetralogy Of Fallot Patient?

I m 18 years old and was born with Tetralogy of Fallot, I had surgery when I was born and again at the age of 10 months. I ve done regular check ups every year and had no further complications. I also do sports regularly and have a healthy lifestyle. I do however feel occasional sudden heart pain for no particular reason, and have also experienced a couple of arrhythmias in the last few months. I occasionally drink alcohol on night outs but I ve stopped enjoying being drunk, so I ve lowered the pace with drinking. I was wondering however, if there were any major risks associated with smoking weed. Not as in making a habit out of it, but trying it out just for fun. I ve never smoked cigarettes or anything else.