I am sorry the skipped beats continue. Sometimes doctors have special plans to help really poor ones, sometimes the state pays a good deal of it. Sometimes towns have special doctors for people who are volunteers to help with those who can't pay. I would inquire around to find out if there are any like this. Also sometimes friends and family or perhaps a good neighbor may help provide money for a need such as this.
Sometimes one can get a bit of extra money selling something they have on a yard sale. These suggestions may help obtain money for the cardiologist if desired. Perhaps the skips were happening before any supplements but I still would be careful about those if the doctor can't be seen for a blood test to check electrolytes.