Gratitude and heart disease

What about people dealing with heart disease?  What can gratitude offer them?  

Psychologist Dr Glen Affleck interviewed 287 people recovering from a heart attack at 7 weeks after the attack and at eight years after.  From this research they found that people who found a positive benefit from their heart attack (and did not blame others for the occurrence) fared better.  These people were less likely to suffer another heart attack within the next eight years.  The researchers concluded that people who looked for benefits from the heart attack (were grateful) faced a decreased risk of another attack.  

 A gratitude quote for today:  If a fellow isn't thankful for what he's got, he isn't likely to be thankful for what he's going to get." Quote by Frank A. Clark at Gratitude Quotes, http://www.abundance-and-happiness.com/gratitude-quotes.html
(Sorry I accidentally left off the source)