Congenital Heart Defect + Marijuana?

Surprisingly I saw this question not too long ago. My main concern in this case is this: if your heart rate raises beyond a certain point, it can sometimes cause arrhythmia which can be a risk for fibrillation (a heart attack basically). If you're running and symptoms begin to develop, you can stop and cool off, and try again tomorrow. If you notice symptoms when you have a chemical reaction causing your heart rate to increase, there is nothing you can do. The risk of sudden death is very low overall, but I would expect that a doctor would advise against taking marijuana and any nonessential drug that can raise your HR. Caffeine in moderate amounts is fine (not energy drinks or pep pills, if you can help it). Is the effect of marijuana any more than a cup of coffee? I don't know, I've never used it. There are a lot of people who never use drugs, so if you decide against it I can assure you that you're not missing any more than us.