The side effects felt from being exposed to second hand smoke are from Carbon Monoxide, Hydrogen Cyanide and some other noxious chemicals that can reach levels that are well above OSHA standards for safety. If a non-smoker happens to have a heart condition or an asthmatic or bronchial problem, and exposure to second hand smoke induces an incident on the spot, it would be said by all that the second hand smoke was more dangerous to that non smoker than the first hand smoke was to the smoker him or herself at the time. But rest assured, if the second hand smoke could induce the attack, if that person had smoked him or herself it would have induced a lot earlier and probably more severely. I have to say probably because the second hand smoke exposure may have fatal consequences for the predisposed non-smoker. But again, if second hand smoke did it, if that person were a smoker they would likely have experienced much sooner from their own self induced exposure.
The best way to keep your exposure to nicotine and the 4000 other chemicals and poisons to a bare minimum is to never take another puff!
Here is a string that visually explains the difference between actually smoking and second hand smoke exposure: Another slant on how to watch people�smoke