Do you have questions about preventing and treating heart disease?
ABC News' medical editor Dr. Timothy Johnson will answer your questions.
As medical editor for ABC News, Dr. Tim provides on-air medical analysis for "World News With Charles Gibson," "Nightline" and "20/20." He has provided commentary on medical problems and answers for viewers of ABC News' "Good Morning America" since the program's debut in 1975.
Please send in your question below.