Always anxited about getting any big disease. Will this anxiety lead me to cardiac arrest? (18 years old male)

Severe anxiety. Clearly you worry way too much. Your info says nothing about heart disease so I have to assume that as an 18 yr old who has never smoked ( very good!) that your heart is healthy. The worry should not lead to cardiac arrest but i bet you would feel so much better if you got some help. Please get a referral for cognitive behavioral therapy and see your doctor about possibly trying some medication.