R66 drops treats disorders of cardiac rhythm i.e., irregular heart beats caused by improper contraction (conduction) of heart muscles following degenerative heart disease. R66 is also well indicated for inflammation of heart muscle (myocarditis & endocarditis), for heart attack (myocardial infarct), abnormally rapid heart rate (tachycardia), functional heart complaints (cardiac neurosis), Adam Stokes syndrome (fainting due to slow or absent pulse).