Sudden Cardiac Arrest (SCA) is the abrupt, unexpected loss of heart function, breathing and consciousness. SCA usually results from an electrical disturbance in your heart that disrupts its pumping action, stopping blood flow to the rest of your body.

Cardiac arrest is the abrupt loss of heart function in a person who may or may not have diagnosed heart disease. The time and mode of death are unexpected. It occurs instantly or shortly after symptoms appear.

A heart rate of less than 60 beats per minute (BPM) in adults is called bradycardia. What's too slow for you may depend on your age and physical condition.

• Physically active adults (and athletes) often have a resting heart rate slower than 60 BPM but it doesn't cause problems and is normal for them.
• Your heart rate may fall below 60 BPM during deep sleep.
• Elderly people are more prone to problems with a slow heart rate.