Each year, over 300,000 Americans die of smoking-related heart disease. So, don't smoke. If you do, quit. The sooner you quit, the sooner your risk will start to decline. There is hope.
Former smokers can completely lower their risk of sudden cardiac death within ten years of quitting.
Because they are foreign substances, any drug can effect your heart. Even prescribed medications can. However, since prescribed medications are legal, doctors are able to control the effect a drug will have on your heart by controlling the dosage. Only if you don't take any. Even a small amount of a drug can be potentially fatal.