Should I Take Cartiaxt300mg Cap As My Pounding Heart Rate

Should I take cartiaxt300mg cap as my pounding heart rate still continue? One doctor said my problems are due to stress and anxiety. I tried every doctor and institution(hospital) but everyone put up stumbling blocks such as "not taking new patients", don't treat Medicare, blue cross insurance only appointment would be January next year. I was given a referral to a psych doc but could not get an appointment.