Nuts like pecans are usually not responsible for causing problems with heartburn as they are not very acidic in nature. Those who already have problems with heartburn though will want to make sure that they steer clear of acidic foods like lemons and oranges as well as other fruits that are highly acidic. It might be a good idea to do a little bit of research so you will be able to see just which foods to avoid so you will be able to prevent problems with heartburn.
Acidic foods tend to aggravate heartburn/acid reflux, so it will be incredibly important for you to take the time to look through your options so you can see which foods to include in your diet. Pecans are classified as being an alkaline food, meaning that they are not acidic in the least and are unlikely to cause problems with heartburn when eaten.