Heart is a vital part of our physical body that sustain life, it acts like a pump pumping out blood to almost all coroners of our body with essential nutrients, more that that it have its spiritual significance
Before explaining the relation between heart and soul, I am gonna ask you a question, just try to point your finger to parts of your body from head to toe and say I, or I am Sarah, I am John what ever your name may be, you have to use your own name, try to find a comfortable area of your body where you can point and say that you are you. I can say all of you may be comfortable pointing your hand towards your heart, you even feel uncomfortable while pointing towards other area including your head and get more comfortable when your hand moves closer to your heart ,So what is so special about the area around your heart, the ‘I’ factor that makes you is somewhere there, the “I” factor that makes you is your consciousness your spiritual self have some relation to that particular area, that is why you can comfortable point your hand towards your heart while mentioning about you.
I believe that our soul can go beyond time and space dimension but your heart area may be an out let towards this physical world, we can compare that to water tap which gives out water from a reservoir and we can compare water tap to heart, can compare reservoir to the timeless space less dimension and can compare water to our spiritual self.
From generations human race are aware of the fact that love is an expression from deep inside our heart our heart ( love and compassion are spiritual expressions )This is my though, I like to know what you think about it?

[...] person is not the physical body, the real person is the soul. The person will remain too close to our heart, because in spiritual world closeness in measured in Love but in physical world closeness in [...]