Your blood pressure can drop during a heart attack. (Blood pressure is a measurement of how hard your blood pushes against the walls of your blood vessels as it moves around your body.) If your blood pressure gets too low, your brain doesn't get enough blood. This makes you feel dizzy or faint. You might even black out.

During a heart attack, your blood pressure may drop for a number of reasons. For example, your heart may be beating too fast or too slow because the nerves that control how fast your heart beats have been damaged. And if the back of your heart or the base of your heart is damaged, this can affect a nerve that controls your blood pressure and how fast your heart beats.

This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment. ©BMJ Publishing Group Limited 2008. All rights reserved.