"In the mid-1970s, the benchmark Framingham Heart Study found that suppressed anger could help predict the incidence of heart disease." LINK
"Let the mind descend in to the heart." (Philocalia, Eastern Orthodox classic on Prayer of the Heart)
"After sunset, having asked the help of the all-merciful and all-powerful Lord Jesus Christ, sit you down on a low stool in your quiet and dimly lit cell; collect your mind from its customary circling and wandering outside, and quietly lead it into the heart by way of breathing, keeping the prayer, 'Lord Jesus Christ, Son of God, have mercy on me,' connected with the breath." (The Monks Callistus & Ignatius, Directions to Hesychasts, 14th C. Orthodox)
"Prayer is constant remembrance of our Lord Jesus Christ, quietly led into the heart by way of breathing and again led out, without any extraneous thought or imagining."(ibid.)
“Breathing out and breathing in, relinquish your mind and enter your heart, the lotus where the energy that creates the universe flows”. (Vijnana Bhairava, Medieval Yoga scripture of India)
Hridayeh chitta-sanghattad drishya-svapa-darshanam: "When the mind merges into the heart, one perceives the true nature of the external world as the dreamlike projection of consciousness." (Shiva Sutras, Kashmir)
(Ramana Maharshi, Vedanta Master), 20th C. Russian painter)
"Don't dismiss the heart, even if it's filled with sorrow. God's treasures are buried in broken hearts." (Rumi, Islamic Sufi poet)
"When the bud breaks, it becomes a flower. When the heart breaks, it becomes divine." (Sri Sri Ravi Shankar, contemporary master of yoga & breath)