Hello and welcome to HealingWell. Many people have EF in the teens range and if you are feeling good I would venture to guess your treatment is working well.
Like you, others are treated for a low EF with diuretics, beta-blockers, ACE inhibitors, defib/pacemaker devices, and low sodium diet.
I would encourage you to contact your Dr. with this very same concerns and I am sure he will discuss your worries with you.
Do let us hear from you re what your Dr. says.