So let's just understand that how serious a heart block is or can be. Heart block is not always serious, but it depends on the type. First degree and even second degree heart block may be managed to with little or no treatment. These types of heart block may have little impact on your long term health or quality of life. Second degree and third degree heart block usually need a pacemaker, but with certain lifestyle changes, you may be able to live comfortably for a long time