What to do when your doctor won't lesten to what is going on. It seems as though he doesn't care any

What to do if your doctor just won't listen. I have PVC's and also misfiring of mthe atrial and ventricular area of the heart. I have coronary artery disease and have had two heart attacks and a pacemaker. Upon calling my doctor he said he is not at all worried about my symtoms even though they take my breath away and cause me not to sleep. Sometimes after I have called the message can lay on his desk for up to two or three days because he has cut back to part time. What do you suggest. These symptoms are so scary because I can't sleep and when it takes my breath away just turning over in bed can leave me with severe shortness of breath.