Nicotine and Heart Disease

Cleveland Clinic Heart Center (webmd.com) says:
The nicotine present in smoke causes: Decreased oxygen to the heart, Increased blood pressure and heart rate, Increase in blood clotting, Damage to cells that line coronary arteries and other blood vessels

and yet the...

American Heart Association Says:
Nicotine Replacement Therapy (NRT) has been shown to be safe in most people with heart disease. However, if you've recently had heart problems, such as an irregular or rapid heartbeat, or chest pain, consult your doctor before using nicotine replacement products.

Why would the AHA support a product that supposedly causes heart disease?