Studies of heart based Healing from HeartMath Institute
Since 1991, the HeartMath Institute has researched and developed reliable, scientifically based tools to help people bridge the connection between their hearts and minds, and deepen their connection with the hearts of others. Since 1983 the heart was reclassified as an endocrine gland, producing oxytocin as well as several other hormones. Their research shows why the heart has been associated with emotional states since ancient times.
Here is a link to the Meta Study of research since 1986 …
The HeartMath Institute Home Page …