For unexplained reasons, young premenopausal women with heart disease have twice the rate of death compared to men of the same age. Animal experiments have shown that stress can reduce ovary function in females monkeys due to reductions in brain hormones. This stress and reduced brain hormone levels lead to low estrogen levels and can cause menstrual cycles to become irregular, leading to reductions in fertility. These monkeys are also more likely to develop heart disease. In order, to better understand this relationship the investigators would like to study estrogen levels in premenopausal women with heart disease.