Commas drive me crazy. Are the below correct? If not, why? 1. Many women are surprised to learn that heart disease is the leading cause of death for women in the United States. 2. Although heart disease has been studied for decades, most researchers have studied male patients. 3. Now, however, scientists are beginning to understand that heart attack symptoms differ in men and women. 4. Unfortunately, many doctors are unfamiliar with the symptoms of heart attacks in women, so their female patients may remain undiagnosed after a heart attack.