He noted that the amiodarone and dronedarone molecules are structurally similar-though the newer drug lacks the iodine moiety that makes amiodarone thyrotoxic-so potentially they could have similar side effects.    From Wordnik.com.  [theHeart.org] Reference

In the current paper, he suggests that the reason thyrotoxic patients frequently develop cardiac arrhythmias may be because they have genetic mutations in ion channels of heart muscle cells that are regulated by thyroid.    From Wordnik.com.  [THE MEDICAL NEWS] Reference