I have had a pacemaker for 2 years now. I started out as 14% dependent and now am 90% dependent. Am on 150 mg Karvea and 50 atenolol in the morning. Have frequent events of heart racing with pain from shoulder to shoulder and up my throat. Today the cardiologist told me to increase the atenolol to 50 mg in th morning and 25 mg in the evening. I am concerned that this will further lower my heart beat and cause a greater dependence. Can you advise?