The two most important centres of human existence are our heart and our brain. The brain controls the whole body with the exception of the heart. The Heart Math Institute have shown that the heart has an enormous magnetic field around itself. The magnetic component of the energy around the heart has been measured to be more powerful than that of the brain. Research shows that the heart field can send synchronizing signals that cause the whole body to vibrate in harmony with the heart.
So if we actively work on our heart frequency through heart meditation the brain waves will be affected which enables a process of development that strengthens our soul.