Knowing how to perform CPR or use a defribrillator during a medical emergency could be the difference between life and death.

Since 2003, the Staten Island Heart Association has worked to prevent heart-related death and disability.

It offers training in CPR and the use of defribrillators.

Non-profit organizations can even learn for free.

"Seventy percent of cardiac arrests happen outside the hospital, or in the home. Chances are, you're gonna help someone you know or love, so it's a really important skill to know," said S.I. Heart Society Director of Operations Rachel Volpe.

The Staten Island-based organization has expanded to hold training sessions across the city.

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