In the case of a heart attack, a person can do the following and save their life even when alone:
Two nights ago I received a call that a dear sister in Christ was having a heart attack. The heart attack caused such severe pain in her shoulders that she could not move and was in tears. Her husband and I sat up with her through the night praying, giving her cayenne and water for the heart, and applying charcoal and comfrey poultices on the shoulder for the pain. By the morning she was normal and ready to go back to work.
To prevent heart attacks: drink lots of water, walk daily, and be sure to keep the limbs covered. When the arms and legs are exposed and become chilled, the blood flows back to the heart, overworking it with every beat. Dress warmly to protect the extremities and your heart.
God is good and "a rewarder of them that diligently seek Him." — Hebrews 11:6 (KJV)