So, I Was Born With A Heart Murmur, I Started

So, I was born with a heart murmur, I started smoking weed about 2 years ago. But I smoked recently and I felt different then normal, my heart was pounding really fast, and I kept blacking out, ever since then I'll have SHORT random black outs. I can't even remember remember half of my lunch period from eariler today. Could the weed use through those 2 years have effect my innocent heart murmur?