A Traditional Chinese Medicine Drug (Tmyx) Controls Heart Rate By Modulation Of The Pacemaker (F) Channels

TMYX is a traditional Chinese Medicine drug used to control cardiac rate in arrhythmic patients. The efficacy and safety of this substance is proved by its clinical use, but the molecular mechanism of action is unknown. TMYX (2 mg/ml) reduces spontaneous rate (−21.9±0.8%, n=11) of pacemaker cardiomyocytes due to a selective reduction of the diastolic depolarization slope (−49.3±3.6%, n=11) caused by a leftward shift of the activation curve of If (−7.1±0.6, n=3) and associated current inhibition.