Can an enlarged left atrium cause seizures?

I recently had a grand mal seizure, and while in the hospital they found I had an enlarged left atrium. Could seizures come from an enlarged atrium? For the past 7 or 8 months i've been REALLY sick, I even became septic at one point. I've always been very healthy, and I never had a seizure in my life before this! I'm so confused as to whats causing all this. I'm only 18 years old! Also, what are side effects from an enlarged atrium? I'll choose best answer :)