See New Testament word study on Heart = kardia
Think of an Air Traffic Controller and how dysfunctional, even destructive it is when the controllers fail to function as they should.
Heart ( 03820) ( leb - note that this discussion also includes the closely related noun lebab - 03824) sometimes refers to a literal heart (Ex 28:29, 1Sa 25:37, 2Ki 9:24), but most often is used figurative to refer to what I term the 'control center' of our being.