Read that study show u can get heart attack smoking marijuana. should i worry about it when hr is in 100-120 region? now i think the heart will stop??

Tachycardia: You seem to have an elevated heart rate, called tachycardia. You are young though. Are you healthy? You have had an echocardiogram, and an EKG? Marijuana may not be a great risk for heart attacks, like cigarette smoking is. It is not without its dangers, as you are starting to think about. Be thoughtful about the substances you use and their effects.